A Typology of Korean Housing Units: In Search of Spatial Configuration

Abstract Space analysis aims to identify the relations between society and space. Space analysis results let us identify the characteristics of the targeted space and subsequent human activities based on the notion of social relationship. The reason authors try to understand spatial structure lies in that it is the intrinsic attribute of physical built environment. This research looks into apartment houses, a widespread form of housing in Korea, in an attempt to investigate the social logic lying in its domestic space by measuring the spatial configuration. This research is based on empirical data and uses a quantitative methodology; Space Syntax. Characteristics of spatial structure in apartment units and their meanings were identified through this research. The implication of the living room-centered layout type most common in Korean apartments was discussed from the viewpoint of the domestic space genotype.

Introduction 1.1 Background and Purpose of the Research
Lifestyles, behaviors, values, and beliefs of a society develop under the mutual influence of the physical environment, and are thus revealed through the structural organization of space. This results from the fact that human behaviors are basically shaped within space and displayed through space. Thus conversely, if authors identify the structural properties of space, authors can reveal human behaviors, predict lifestyles, and further discuss social phenomena from spatial structures. Studies on domestic space, on the other hand, can be extended to diverse cultural studies through microscopic approaches. This is enabled by the fact that housing can be explained as a society's cultural phenomenon which exposes the features and meanings of the time. In other words, housing is the product primarily of socio-cultural factors of the society (Rapoport, 2001). In this respect, Korean apartments are no doubt an interesting research topic. Korea, with its collectivist and homogeneous cultures, has achieved rapid economic growth, during which it has also undergone many changes in housing, both cultural and physical, in a short period of time. Apartments came to be the most prevailing housing type in a relatively short time in Korea, and at the same time, have been preferred by many people. Thus, this research focuses on the apartment housing type and the spatial structure of its domestic space. This research is based on the premise that dominant apartment types in Korea will display certain structural features of space. The purpose of this research is to identify, from an objective viewpoint, the socio-cultural implication of the apartment's domestic space by looking into the structural properties of space.

Scope and Method of the Research
This research started from the question of whether the typical spaces of Korean modern housing have any topological characteristic, and was further developed by applying the following research scope and methods. The spatial scope of this research is restricted to an apartment's interior domestic space. The bounds of domestic enclosure can be extended from internal to external bounds if authors consider the residents' movement tracks. Also, there exist boundary spaces in between. Interior domestic space, however, holds an important place in residents' living patterns in that it must serve as a home, as well as meeting the basic functional needs as a shelter. The structure of interior domestic space within an apartment is determined by its spatial configuration. Planar spatial configuration is exposed through the floor plan. Thus, spatial configuration will be addressed in this research, the determinant for the spatial structure in an apartment unit plan.
Space Syntax theory was applied to domestic spaces. Also, precedent researches were reviewed relating to Korean apartment units, through which a space analysis methodology was developed for identifying the structural properties of space. This study consists of two parts: a quantitative analysis on spatial configuration and exploration of the domestic space genotype of Korean apartments. The first relates to data analysis and results, the latter to the interpretation of the analysis results.

Literature Review 2.1 Spatial Configuration of Domestic Space
The advantage of representing topological relations of spatial features is that it allows clear understanding of spatial structure by simplifying the connections between spaces. There can be differences in the degree of integration or segregation among domestic spaces with seemingly similar configurations. In other words, plans with similar layouts can still have spaces with different structural features depending on how they are connected with one another. Apartment units can have similar plan layouts, which particularly makes it difficult to quickly and directly grasp the connections between spaces. This is because the 'structure' of space is not immediately apparent on the surface. Many researchers have examined spatial layout patterns of domestic space. The methodology used most often is to identify and draw integration or segregation patterns of space out of spatial layout properties based on plan design. Hillier et al.' thesis (1987) was the first to apply this research methodology. It confirmed the genotype based on the spatial layout patterns by analyzing seventeen farmhouses from the Normandy region of France. The genotype was determined by the common characteristics drawn from identifying each space's order of integration within a plan and structuralizing them into a graph.
Then how will the genotype be defined here? Genotype is broadly defined as features or phenomena that persist over time. It is cloned from generation to generation, and repeatedly expressed in multiple cases. In a similar vein as the precedent research, the genotype of domestic space can be defined as the spatial layout patterns that commonly emerge from multiple cases.

Apartment Unit Plans in Korea
Precedent studies concerning Korean apartment units can be divided into (a) ones that analyzed spatial structure to investigate changes in plan or the evolutionary process of Korean traditional houses and (b) ones relating to plan archetypes and typologies. If we look at the researches analyzing the spatial structure of traditional versus modern houses to interpret its implications, one significant study (Choi, 1990) confirmed that the apartment living room assumes the role of the Korean traditional courtyard, which was brought indoor in modern apartments and persists as a focal space for family life. It proved Korean traditional spatial activities can successfully be reenacted in modern apartments. Other studies (Choi, 1996a and1996b) investigated apartments located in the Seoul metropolitan area to analyze changes in plan and lifestyle and interpret its implications by tracking topological changes of each space in a unit plan. These works are significant in that they practically proved that Korea's socio-economic changes have been clearly reflected in apartment unit plans.
Otherwise, the evolution of domestic space was explained as a topological transformation process of adapting to new housing types by differentiating floor levels for separate spaces (Seo, 2003). Seo argues that the Korean traditional courtyard has been transformed into modern apartments' lower floor level spaces, such as entrances, balconies, bathrooms, storages, etc., based on the notion of 'spatial activities' and the distinction between lower and higher floor level spaces. Seo's research suggested a new possibility for interpreting the genotype which can differ depending on hypotheses and viewpoints for analyzing the evolutionary process of a certain space. Other studies (Kim et al., 1992) on the plan typology developed general patterns for plan based on the number of rooms, spatial layout for living room, dining room and kitchen, doorways, and the number of front bays. Looking at studies concerning the archetypal elements of plan, a set of archetypal spatial elements were suggested as a conceptual framework for explaining changes in Korean house plans. These elements were defined as 'ondol', 'maru', and the service area 'bueok' which have emerged anywhere, at any time in Korea, and their grouping and integration patterns were presented (Jeon et al. 2008).
The literature review suggests that this research has significance with respect to research scope, analysis data, and methodology. This research limited the time period of analysis from 2001 to 2013. Precedent studies set the time period to the early 2000s, whereas this study concentrated on spatial configuration patterns for plans from 2000 and includes the latest cases where various spatial layouts were attempted. While the years from 2001 to 2005 had witnessed the beginning of the branding and gentrification of apartments, such phenomena intensified and specialized designs appeared during the period from 2006 to 2013. In the early 2000s, apartment brands started to gain recognition in place of construction companies' brands themselves. In 2002, Green Building Certification Criteria (GBCC) was implemented in the public housing sector. The construction law was revised in 2005 to legalize balcony extension. Other changes included more concern about the quality of life and cultural activities which mirrored the introduction of a five-day workweek. Public awareness on the importance of green lifestyle practice also started to grow in households. If authors look at the period from 2006 to 2013, the notion of green building became popular and the sustainability paradigm, covering the green building issues, spread. The gentrification of apartments brought further specialized plan designs. Specialized apartment designs for vertical extension, low-rise terrace types, multi-home types, etc., were developed, with the related patents being applied for. This research is distinctive in that a complete enumeration survey was done for data collection, not just a randomly sampled dataset. The overall research framework for this study is based on Space Syntax theory. However, statistical analysis was conducted in addition to the existing space analysis methodology.

Material and Method 3.1 Data Collection
Unit plans for apartments built in the city of Seoul from 2001 to April 2013 were collected for analysis. Of those collected, only three-bedroom and fourbedroom types were used for the research. Data collection was done in two parts: the compiling of lists of unit plans, and the collecting of plan images. As this research aimed for a complete enumeration survey, a complete listing of the population was quite important. Apartment Encyclopedia: Seoul was referred to for the preliminary listing. The book has a complete list of apartment complexes located in Seoul, with basic information including titles, locations, the number of units, etc., and unit plan images. For data since 2006, the web portal "Naver Real Estate" was used for search by administrative region. Data collected from the web were cross-checked against the preliminary listing and complemented to complete the final list. The final list included a total of 2,500 plans. Plans for threebedroom types amounted to 1,757, those for fourbedroom types to 743. If authors look at the years 2001 to 2005, collected plans amount to 1,277, 842 for three-bedroom types and 435 for four-bedroom types. For the period 2006 to 2013, plans amount to 1,223, 915 for three-bedroom types and 308 for four-bedroom types.

Analysis Method
Spatial structure analysis of unit plans was carried out in three phases: first, the setting of unit space and representation of spatial structure; second, selecting analysis indexes and tools; and third, statistical analysis for the space analysis results. Methodologies developed for each phase are as follows.
First of all, spatial structure within a unit plan is represented as a series of convex spaces. This is done by creating a convex map. One convex space corresponds to one unit space. Representation scope for spatial structure of a unit plan includes all the rooms defined by walls within the unit: entrances, living rooms, kitchen and dining, master bedrooms, other bedrooms, bathrooms, master bathrooms, closets, powder rooms, balconies, storages, etc. While every room will be included in the spatial structure representation, for the result analysis, we will only focus on the following spaces: the outdoor (of an entrance), entrances, living rooms, kitchen and dining, master bedrooms, other bedrooms, and living room balconies. Bathrooms, corridors, family rooms, other balconies, and storages were excluded from the analysis.
Next, authors selected integration as the analysis index for examining spatial structure properties. Space analysis methodology uses several indexes that quantitatively represent various spatial structure properties, such as connectivity, control value, Fig.3. A Unit Plan and its Convex Map legibility, etc. Integration index, representing the topological centrality of a space within the plan, is the principal measure of spatial structure properties. The most integrated and segregated spaces within a unit plan can be located using the integration value of each unit space. The overall spatial layout pattern will be mapped and its characteristics will be examined. 'S-cube Convex Analyzer v 2.1' was used for the space analysis. Using this tool, convex maps created in AutoCAD were imported and after running the analysis, integration data for each unit space were exported into an Excel spreadsheet.
Lastly, the analysis results were statistically processed. Analysis results for each test case-the integration values for each space within the planare used as raw data for statistical processing. The statistical techniques employed are factor analysis and cluster analysis. The varimax rotating method was applied for factor analysis out of principal component analysis and orthogonal rotation methods. After examining accountability and reliability of the data, spaces with high accountability are identified by period and plan type. Also, factor values gained from it are inputted as independent variables for the cluster analysis.
T h e K -m e a n s m e t h o d u s e d m o s t o f t e n f o r nonhierarchical cluster analysis was applied for extracting the clusters. The number of clusters was set from two to nine. After the analysis run, cases for each cluster were examined. Three groups were finally selected, whose characteristics were distinct and the clustering patterns were significant. Cases within each cluster and their spatial layout features were examined and after that, the level of centrality for some specific spaces was compared to one another to discover differences between clusters. SPSS 20 was utilized for the statistical analysis.

Result Analysis 4.1 Factor Analysis Results
Factor analysis results revealed that all KMO values were over 0.6. For the period 2001 to 2005, the three-bedroom type accounted for 83.9% of the total dispersion, and the four-bedroom type accounted for 73.8%. For the period 2006 to 2013, the three-bedroom type accounted for 59.9%, and the four-bedroom type accounted for 69.6%. Factors demonstrating high accountability as overall cumulative accountability reached over 60%. However, both types showed lower accountability than before during the period 2006 to 2013. The reason for this should be specifically addressed in further analysis, because it means that the overall data's accountability became lower. For the two periods, unit spaces with only the same functions are selected and applied as variables. Unit space variables are reduced to two to three factors to show different results from one another, and cumulative dispersion also became lower, requiring interpretation in multiple aspects based on factor analysis results. Looking at each unit space's grouping pattern, entrance loaded on factor 1, a major factor, whereas living room was included into factor 2. Other spaces, however, displayed different patterns depending on the period and the number of rooms. This implies their accountabilities were affected by different factors. A closer look at factors for each floor plan by period is presented below.
The period 2001-2005 witnessed extraction of three factors for both the three-bedroom and four-bedroom types, but unit spaces loading on each factor differed. Entrance/bedrooms, living room, and kitchen-dining room loaded on each of the three factors for the threebedroom type. Entrance, living room/kitchen-dining room, and bedrooms loaded on each of the three factors for the four-bedroom type. It is notable that living room and kitchen-dining room loaded on separate factors for the three-bedroom type, whereas both loaded on the same factor for the four-bedroom type. In other words, living room and kitchen-dining room can be said to demonstrate different accountability from each other, as they were grouped into different factors for the three-bedroom and four-bedroom types respectively.
The period 2006-2013 witnessed the selection of two factors for the three-bedroom type, and three factors for the four-bedroom type. Entrance, bedrooms, and kitchen-dining room all loaded on factor 1, while living room loaded on factor 2 for the three-bedroom type. One can assume changes in kitchen-dining room as it loaded on a major factor compared to the period before. For the four-bedroom type, entrance, kitchendining room, and bedrooms loaded on factor 1, living room on factor 2, and master bedroom on factor 3. Changes in relations between bedrooms and other spaces can be detected, compared to the previous periods. Unit spaces loaded on different factors from one another, and their accountability of variance showed difference. The degree of spatial integration or segregation mostly affected the factor loading pattern, as the integration index was used as variables for factor analysis.

Cluster Analysis Results
The results of the cluster analysis are provided in a table format, where A, B, and C denote the order of clusters from the highest number of cases to the lowest. The same cluster label does not necessarily indicate the same spatial structure properties. The rank order indicates the order of mean integration for each space within the cluster. Plans within each cluster were extracted conversely from the rank order and then tracking the raw data.
The result has showed that in many cases, living room demonstrated high centrality. This means that the spatial layouts tend to be living room-centered in general. There were differences, however, in the degree and order of centrality between living room and other spaces. Also, there were a few cases where kitchen-dining room displayed high centrality. Notable trends from the cluster analysis results are presented below by period and number of bedrooms.
In the period 2001-2005, cluster A and B of the three-bedroom type showed the rank order of centrality as follows: living room, kitchen-dining room, master bedroom, and entrance. Cluster C had the lowest case rate, where kitchen-dining room displayed the highest centrality. The deviation between kitchen-dining room and other spaces was quite large. Cluster A of the fourbedroom type had the highest case rate of 89%, where living room showed the highest centrality. Next to living room, living room balcony and kitchen-dining room were ranked in the order of their integration value. Cluster B and C showed a very low deviation of centrality for each of the spaces.
The three-bedroom type in the period 2006 to 2013 had balconies with increased centrality and master bedroom with lowered centrality compared to the previous period. Kitchen-dining room was ranked higher than for the four-bedroom type. As living room balconies are placed adjacent to the living room, their rank order can be interpreted as the living room being relatively centralized. Master bedroom displayed a more segregated pattern than before. Changes in spatial layout pattern also directly relate to changes in spatial functions and roles. Cluster A and B showed the rank order of centrality to be living room, kitchen-dining room, and living room balcony. Living room balcony displayed increased centrality than before. However, entrance became segregated. Cluster C had the rank order of centrality as kitchen-dining room, master bedroom, and living room. A number of four-bedroom type cases turned out to have living rooms with high centrality. However, the percentage has declined compared to the previous period, which is notable. It shows a clear difference from the three-bedroom type in terms of spatial configuration. Cluster A showed the rank order to be living room, living room balcony, and kitchen-dining room. This demonstrates a typical spatial layout where the living room's centrality is emphasized. Kitchendining room turned out to have high centrality in cluster B, whereas the difference with that of living room was minimal.
The case rate of each cluster was identified from the cluster analysis results. The cluster with the highest case rate can be seen as a meaningful archetype. It was also demonstrated that a difference exists in spatial layout properties among clusters. That is, from 2001 to 2003, living rooms were placed in the topological center within a unit plan. This is the feature that has been identified through a number of cases. This living room-centered spatial layout was extracted as a common feature, but differences existed in the inside.

Spatial Configuration and Society 5.1 Why Living Room?
As can be seen from the analysis results above, the rate of living room-centered plans was overwhelming from the 2000s until recently. The three-bedroom type showed strong tendency of the living roomcentered layout, while layouts for spaces other than living room-master bedroom, entrance, balconies, etc. -varied. The four-bedroom type also showed Then what is the background for this prevalence of living room-centered layout in apartment unit plans? This can be understood in a twofold way: from the viewpoint of structural properties resulting from spatial configuration; and the acceptance of life style.
First, authors will examine the spatial structure properties of living room. This can be explained by spatial layout principles applied to traditional houses and apartment unit plans. A living room represents the center of a house plan. A living room does not simply support only public functions in household life. It provides passages for movement to other spaces. This has been identified in a spatial structural viewpoint. An apartment living room assumes the role of the courtyard in Korean traditional houses, 'Hanok', in a topological sense. Also, the living room serves as a focal place in household life which is visually integrated within a housing unit (Choi, 1990). This research confirmed that this is still true at the present time, when apartments have become pervasive.
The courtyard that once served an important role in traditional life came to reappear as the form of living room in an apartment, and as a result, our traditional life style could successfully continue… Unlike in other countries, Korean apartments were successfully introduced and settled as one of our housing types, the reason for which is it symbolizes modernization on the external side and at the same time, fully accepts our own life style on the internal side (Choi, 1990).
Thus, the second viewpoint will be that the spatial layout properties of the living room within apartments and the spatial functions formed from them conform to Korean life style. This is because the apartment housing type started to accept life style in a Korean context from the beginning. Apartments have experienced many changes since the 1960s when they were first built. The living room-centered plan was not the only type attempted, however. A so-called western type of plan layout that clearly separates public and private spaces was once attempted, but it didn't last (Kang et al., 1999).
Thus, the living room-centered spatial layout identified by the analysis results of this research proves that the spatial functions provided by the living room are still of importance in a household space. Also, the research results demonstrate that this type of spatial layout principle easily accepts nowadays diverse and complicated life styles. To put it differently, the function and layout properties of the living room have resulted from the fact that they conform to Korean people's way of living. Domestic space has been partly changed or unchanged according to the times, socio-cultural factors, family structures, etc. Spatial configuration of the unit plan can also be explained through its parts that have changed and parts that have not changed. The unchanged part would be the living room-centered spatial layout, while the changed part would be the degree to which living room is integrated within the whole spatial configuration. In the living room-centered spatial configuration, the deviation of centrality between the living room and the other spaces depends on the connectivities between spaces other than the living room. That is, while the living room's status as a topological center within the plan is still maintained, it is suggested that the spectrum inside it can be interpreted in various ways. This is enabled by the fact social changes in Korea are reflected in domestic space, the physical substance itself.

Genotype and Social Logic of Domestic Space
Apartments became the dominant housing type in Korea in a relatively short period of time. Although it first started from the west, it was accepted and developed in a Korean context. This can be explained as the 'social logic' inherent in space. The fact that socio-cultural concepts are reflected in the physical substance can be discussed with the issue of the genotype which can be raised for the structural properties of space. Earlier studies that extracted genotypes by using Space Syntax have drawn the genotypes based on unit spaces' integration or segregation patterns. Identifying these patterns would be the most objective methodology that can extract and interpret the common attributes of spatial structure, as well as reveal its properties.
However, the genotype of unit plan can be criticized as being a standardized, uniform one in terms of architectural planning. These criticisms do not only point out plans, which result from the planning practice, but are more like pointing out the assembly of plans, layout of buildings, or even the site planning. Also, structure of space is not visible on the surface, but is an intrinsic property that is a totally different matter of discussion apart from the shape of space. Thus, one must be aware that the genotype of spatial structure is a fundamentally different issue apart from these criticisms. The genotype in terms of spatial structure is a commonly emerging spatial configuration pattern from a number of cases. This research looked into unit plans from 2001 to early 2013 to find out that plan cases implementing the living room-centered spatial layout had higher ratios.
Today's apartment does not exist in the West, nor in China, nor in Japan, nowhere except in Korea. It is a housing typology unique to Korea, and the possibility for globalization lies here (Jeon et al., 2008).
This result implies that the living room-centered spatial layout can be interpreted as the genotype of spatial structure emerging in the unit plans of Korean apartments. First of all, it can be discussed in terms of life style. The genotype for unit plan can widely accept life styles from Korean traditional household life to modern household life, and is still being maintained. In other words, it has significance in that it compromises life styles before the introduction of apartments and at the same time, accepts today's changing life styles. Next, the genotype can be discussed from a sociocultural perspective, further to the housing culture. Spatial structure of housing enables the interpretation of family structures, housing culture, socio-culture, and even the times. Thus, the genotype of unit plan needs to be considered in terms of structural properties of space within a comprehensive framework and its internal changes. The comprehensive framework will possibly relate to Korea's socio-cultural distinctiveness such as homogeneity, and inside it can reflect social changes or the current of the times.

Conclusion
This research attempted to objectively identify the implication of apartment housing from a Korean sociocultural point of view, by searching the structural properties of space. Through a literature review, the research scope was set to the period from the 2000s and the spatial structures of the cases were analyzed. The analysis results revealed high case rates of the living room-centered spatial layout type. This supports the fact that spatial configuration found in Korean traditional housing is still present as a modified form in modern housing, and accepts the modern household life as well. The research results particularly suggest that it can be reinterpreted as the genotype of spatial structure which is inherited from generation to generation. This research utilized a quantitative methodology; Space Syntax, to draw principles for the spatial layout of apartment unit plans. This research is significant in that it clearly identified the analysis results from an objective perspective. However, it only addressed cases built after the 2000s and only apartment cases were treated out of all existing housing types. Followup studies will be complementary to this study, in which the periods after the introduction of apartments until recently will be examined, and changes in spatial structure properties will be identified in detail.


Comparative Analysis of VNSA Complex Engineering Efforts

The case studies undertaken in this special issue demonstrate unequivocally that, despite being forced to operate clandestinely and facing the pressures of security forces seeking to hunt them down and neutralize them, at least a subset of violent non-state actors (VNSAs) are capable of some genuinely impressive feats of engineering. At the same time, success in such endeavours is not guaranteed and VNSAs will undoubtedly face a number of obstacles along the way. A comparative analysis of the cases also reveals new insights about the factors influencing the decision to pursue complex engineering efforts, the implementation of such decisions and the determinants of the ultimate outcome. These result in a set of hypotheses and indicators that, if confirmed by future research, can contribute to both operational and strategic intelligence assessments. Overall, the current study enriches our understanding of how and why VNSAs might engage in complex engineering efforts. Acknowledgements This work was supported by Sandia National Laboratories, Contract #1525332. Any opinions, findings, conclusions and recommendations in this issue are those of the authors and do not necessarily reflect views of Sandia National Laboratories or the U.S. Department of Energy. This article is available in Journal of Strategic Security: https://scholarcommons.usf.edu/jss/vol9/iss1/ 10

Introduction
Close observers -whether in law enforcement, intelligence agencies or academia -of particular terrorist groups and transnational criminal organizations (TCOs) have long been aware of the technical prowess sometimes displayed by their subjects. Yet, those who study violent non-state actors (VNSAs) more broadly, where the relatively straightforward application of firearms, explosives and telecommunications are the overwhelming norm, can sometimes be misled into viewing these exploits as the limit of VNSA capabilities. 1 The preceding cases, however, have demonstrated unequivocally that, despite being forced to operate clandestinely and facing the pressures of security forces seeking to hunt them down and neutralize them, at least a subset of VNSAs have shown themselves to be capable of some genuinely impressive feats of engineering. If these cases (the basic features of which are shown in Table 1) do nothing more than give pause to those who too easily dismiss the potential threats posed by nonstate actors, they will have served a useful purpose. For a complete discussion of the literature and theory surrounding complex engineering efforts by VNSAs, as well as the methodology and case selection process, see the Introduction to this Special Issue. 2 As described in the Introduction to the Special Issue, the AQ Khan network is presented not as a case of complex engineering itself, but rather as an example of how an illicit network might facilitate and support such an effort. It is therefore analyzed separately from the other cases for most purposes in this analysis and is differentiated from the other cases in the table with italics.

Decision
Still, the case studies have a lot more to offer in terms of providing insights into the characteristics that are associated with VNSA complex engineering efforts. Beginning with the decision to engage in complex engineering efforts, Table 2 below summarizes several aspects of the decision making process across the case studies (the A.Q. Khan nuclear case will be discussed separately). For the general context in which decisions were made, in all cases the actual decision to engage in the complex engineering effort was made by the central decision-making body in each organization. Irrespective of who actually carried out the effort, in all cases the organization's senior leadership had to at least give the go-ahead. While there might have been consultation with and input from lower level organizational personnel, it appears that since the effort under consideration represented a major new initiative, requiring the investment of substantial organizational resources and often entailing sizeable risks, it was not left up to functional entities or field commanders to make the key decisions, which occurred in a top-down fashion.
Another common feature across all the cases was the high risk tolerance displayed by the organization's decision makers more generally. While the small number of cases and the absence of negative examples make it difficult to state that a high tolerance for risk is either necessary or sufficient for deciding to engage in a complex engineering effort, it is striking that none of the VNSAs studied could be characterized as being operationally conservative in any way. Moreover, a perceived urgency to act did not seem to color most of the VNSA decision making. While leaders may have perceived a clear strategic need to do something different, in no case (with the exception of Aum Shinrikyo, which had a prophesized deadline only a few years hence) was there evidence that the leaders felt the need to make the decision quickly or rashly. Embarking on a complex engineering effort was therefore mostly a reasoned decision, one that likely estimated the various costs and benefits involved.
Turning to the key question of what factors contributed to the decisions themselves, while the specifics vary considerably across the VNSAs studied, there are several commonalities in the overall motivational formula. This can be discerned by viewing the interacting effects of different levels of motivation that underlie the decision to engage in a complex engineering effort. Across the cases, (1) the basic motivational disposition of the VNSA itself exerts the broadest stimulus by determining more proximate strategic goals. It is these goals that (2) in turn produce the tactical requirements that (3), often in reaction to external circumstances, then provide the impetus for the organization to make a change in its operations. Lastly, it appears that (4) a variety of contingent and contextual factors influence the selection of a particular solution to the operational problem that involves a complex technology, as well as the decision to engage in an internal engineering effort to obtain this technology. For example, in the case of the PIRA, their fundamentally ethnonationalist conflict against the British pushed them to attack police and military targets, which in turn sparked a search to tactically overcome the high-walled fortifications surrounding these targets, while several contextual factors, including particular tactical requirements in an urban environment and a distrust of externally sourced armaments, led them to pursue their own mortar systems. Similarly, the FARC, which had evolved to pursue financial gain, was driven to make operational changes by increased interdiction rates by counternarcotics authorities, while the advantages in terms of carrying capacity and detection avoidance, together with a high return on investment, prompted the decision to pursue a submersible development program. One salient motivational factor to note is that in every case studied, the desire on the part of the VNSA to alter its operational posture was prompted by some change in the VNSA's strategic or tactical environment, whether it is an electoral loss (as in the case of Aum Shinrikyo), or the persistence of multiple rivals in illicit markets (as in the case of the Zetas). It can thus be hypothesized that complex engineering efforts by VNSAs are much less likely to arise spontaneously where an organization perceives itself to be enjoying tactical and strategic success in terms of reaching its immediate goals.
A second hypothesis suggested by the cases is that a complex engineering task is more likely to be undertaken in the absence of any simple alternatives that will solve the operational problem that the VNSA is confronted with. This accords with the general theory that VNSAs tend to be conservative and imitative in their operations and will in most instances pursue the path of least resistance. A corollary to the hypothesis is that a complex technology will usually be sought only if there exists no simple technology that will suffice and that a VNSA will usually decide to engage in an internal engineering effort to acquire the technology only if no external suppliers are readily available or if external supply poses too many security risks.
It also appears that, even though the VNSAs studied were willing to take large risks, they did not undertake complex engineering projects on the off chance that they might be successful. In all the cases studied, leaders seem to have made the final decision to embark on such an effort only if they had at least some degree of confidence in their groups' ability to pull it off. Whether the source of this confidence lay in having copious resources, professional cadre, prior experience in similar technical areas, or even a delusional faith in prophecy (as in the case of Aum Shinrikyo), the decision was made based on some expectation of success, at least in the long run. Another hypothesis is therefore that a positive decision to pursue a complex engineering effort will be far more likely if factors can be identified that might boost leaders' confidence in their efforts' ultimate success.
In at least two of the cases (the PIRA and Los Zetas), the desire for prestige likely played some role in the decision. Here, the very act of the VNSA undertaking a complex, risky and resource-intensive effort might have been perceived as valuable in terms of messaging to opponents, rivals or followers that the organization was one to be reckoned with. While likely neither to be a necessary nor sufficient criterion, it can thus be hypothesized that where an organization is especially concerned with its image as a sophisticated, innovative actor, a desire for prestige can be a powerful facilitating factor in the decision to engage in a complex engineering effort.
The case studies support many of the broader findings and theories of how and when VNSAs decide to innovate, as outlined in the introductory article. Several of the drivers of innovation mentioned in the literature, such as countermeasures by security forces and a greater desire for status, are reflected in the cases. So is causal variation in the decision making, although the cases of complex engineering efforts presented in this volume point towards a more generalizable decision framework (as described above) than is discernible in the broader VNSA innovation context. The importance placed in the literature on a willingness to take risks and organizational learning is also echoed by the case studies. Another factor is the facilitative effect of internal champions, which is alluded to in several of the cases. However, because the champions in the cases tended to coincide with the senior leadership of the VNSAs, it is not possible to identify an independent effect of internal or external champions.
Factors identified in the literature on VNSA innovation that were not supported (but also not contradicted) by the majority of the case studies were: The effects of demonstration of the technology by other VNSAs 3 on the decision to pursue a complex engineering efforts (since most of the complex engineering efforts had never been undertaken by VNSAs previously), whether a self-sustaining momentum developed that would have continued to drive the efforts even in the absence of the initial stimuli, and the extent to which the possession of institutionalized R&D organs or safe havens contributed towards the decision to engage in these efforts. However, related to this last area, possessing high levels of resources seem to be particularly important in the context of the decision to proceed with a complex engineering effort, which would not necessarily be the case with broader VNSA innovation. Given the selection of case studies of only positive decisions to pursue, several findings in the literature, such as the disincentives for innovating in the presence of internal discord or high pressures from security forces, could not be explored in the current study.

Implementation
The case studies make perhaps their greatest contribution with respect to exploring the implementation of complex engineering efforts by VNSAs, given that there is scant existing literature on this topic. Table 3 summarizes the implementation aspects examined across the five relevant cases. First, from the time frames over which implementation occurred, it is immediately apparent that complex engineering tasks are not generally implemented very quickly, at least not to the extent that they return results that can be regarded as unqualified successes. It appears to take a minimum of several years' worth of effort to yield even modestly successful outcomes (as in the cases of Aum's chemical weapons), and can take upwards of a decade or more to achieve the fully-realized outcomes initially envisaged by group leaders (as in the cases of PIRA mortars and FARC "narco-submarines"). It can thus be hypothesized that complex engineering efforts by VNSAs take a considerable amount of time, at least relative to the highly dynamic environment within which most VNSAs operate. If confirmed, this would suggest that law enforcement, intelligence and military agencies have a sizeable window in which to detect and interdict such efforts. Hezbollah; Iran; Gulf states

Concern with Safety
Less concern early period; more concern later (moderate overall) High Low Low Unknown (likely moderate) Second, and acting to some extent in a countervailing fashion to the previous point about windows of opportunity for law enforcement and intelligence, across all of the cases the complex engineering efforts studied took place in locations wherein the VNSAs could operate in relative security, with a good chance of remaining unmolested. The PIRA enjoyed some degree of sanctuary in the Republic of Ireland while developing their mortars; Aum Shinrikyo was protected by the Japanese government's reticence to scrutinize religious movements and the isolation of their Australian property; FARC conducted its "narco-sub" operations in inaccessible jungle areas; the Zetas enjoyed near impunity in many regions of Mexico where corruption had infested civil society; and Hamas controlled the territory of Gaza when it built its operational tunnels. The existence of VNSA safe havens can therefore be hypothesized to complicate counterterrorist or counter-criminal attempts to detect or interrupt complex engineering efforts.

Concern with Security
Third, in terms of who within the VNSA is tasked with implementing the complex engineering effort, in almost all the cases the responsibility was given to a specialist technical or logistical organ in the group, whether this was institutionalized (as in the cases of the PIRA, Hamas, and Aum Shinrikyo) on a broader scale in the organizational structure or more ad-hoc (as in the cases of FARC and the Zetas). Complex engineering efforts by their very nature are highly technical and will almost always represent a radical departure from standard operating procedures within the VNSA. This accords with the more general theory that dedicated, separate R&D organs can bolster the chances of success when VNSAs choose to innovate; indeed, in the context of complex engineering efforts, this might be more of a requirement than a facilitating factor. The existence of a well-resourced, specialized entity endorsed by the leadership might thus be a necessary precondition for any serious attempt to realize a complex engineering effort, which in turn might provide specific, moderately diagnostic indicators 4 for intelligence analysts observing the VNSA.
Fourth, with respect to the types of expertise needed, these vary considerably across cases, although-as is to be expected-various types of engineering (including electrical, aeronautical, chemical, structural and mechanical) feature prominently. Much of the required expertise appears to have come from professionals who had been previously trained, whether this could be found among existing members (as in the PIRA and Hamas cases), members specially recruited for their expertise (as in the case of Aum), hired consultants (in the case of FARC), external actors lending assistance (Hamas), or even coerced technicians (in the cases of FARC and Los Zetas). While there was also some internal development of expertise, for example by sending members for professional training (PIRA) or a process of trial and error (PIRA and Hamas), it can be hypothesized that in most cases VNSA complex engineering efforts will involve some degree of externally-sourced professional expertise, at least if the organization is keen on keeping the length of the development cycle to a minimum. Thus, contrary to the literature on general VNSA innovation, professional technical expertise, beyond a generally proficient and stable membership, might be necessary. If confirmed, this can provide opportunities for detection of complex engineering activities by VNSAs.
Conversely, when it comes to the source of needed materials, in almost every case at least a significant portion of these materials were purchased from commercial suppliers, albeit often under the pretext of legitimate commerce, e.g., through front companies. While there was some assistance from state sponsors (in the case of Hamas and the PIRA), and some acquisition from illicit networks, in none of the cases studied was there outright theft to obtain materials, which would have provided a useful indicator of activity. If the reliance on legitimate purchase for materials applies more broadly than the cases studied, this potentially makes it more difficult for intelligence and law enforcement agencies to detect most complex engineering efforts through material acquisition activities, unlike the case with, say small arms, explosives and nuclear materials acquisition.
Fifth, although many of the cases involved at least some collaboration with outside entities, except for the professional expertise provided from outside (which generally occurred on an individual basis), it appears as if collaboration with outside actors, such as states or other VNSAs was not entirely necessary. For example, Libya provided the PIRA with high explosives, which certainly assisted in their production of mortars, but even before this, the PIRA had succeeded in creating operational mortars using home-made explosives. Similarly, while Hezbollah may have assisted Hamas in designing attack tunnels, Hamas had decades of internal Palestinian experience with smuggling tunnels to draw upon.
Sixth, organizational concern with the safety of general VNSA members involved in complex engineering efforts is variable across the cases, although it is interesting to note that the only group which unequivocally paid careful attention to its members' safety was Aum Shinrikyo, which was also arguably the least successful of the cases studied in terms of its complex engineering endeavors. This does not necessarily contradict the assertion in the literature that key members with technical skills and experience will be protected, since the cases mostly do not reveal how the safety of these key implementers was regarded within the organization. In the related matter of how much operational security VNSAs employed during their complex engineering efforts, this was generally moderate to high, with the key determinant apparently the degree to which the organization believed itself to be vulnerable to security forces.
The last aspect of implementation and a particularly important one involves the obstacles experienced during the process and how the VNSAs responded to these obstacles. It is immediately apparent from the cases that, as expected, almost any endeavor undertaken by a VNSA that qualifies as a complex engineering effort is almost certain to face at least some obstacles along the path from conception to execution. One assumption, which spans the relevant literature and which applies to all of the obstacles discussed below, is that as the complex engineering task in question becomes more complex and more technically demanding, the potential obstacles become greater in number and severity. While the case studies do not confirm this assumption as such, they certainly do not contradict it either. In every case studied, the VNSA under consideration experienced at least one (and often more) serious impediments to success. These ranged from defects in design (e.g., PIRA and FARC), lack of access to materials (Aum Shinrikyo), operating in difficult terrain (Los Zetas) and having to avoid government forces during implementation (Los Zetas and Hamas).
However, in the case of all but Aum, a common thread amongst the various responses was perseverance in the effort despite setbacks. It was only in the Aum Shinrikyo case of nuclear weapons where the group abandoned their plans and switched back to chemical and biological agents; it might not be coincidental that this is the organization that ultimately enjoyed possibly the least success from a purely engineering point of view. Besides perseverance, the VNSAs employed a variety of means to overcome obstacles, including making iterative technical improvements, bringing on additional expertise, replacing infrastructure lost to security force activity and increasing their resource investment in the project. Each of these, however, can be seen as an adaptation to an internal or external impediment. It can be hypothesized that VNSAs that possess sufficient fortitude to persevere in the face of setbacks and that have the capacity to devote additional resources (including personnel, equipment, and funding) to a complex engineering effort are far more likely to succeed in the face of almost inevitable obstacles. Conversely, those VNSAs who lack suitable depth in motivation and capability are hypothesized to be far less likely to succeed in complex engineering efforts in general.

Outcome
Most of the cases studied (with the notable exception of Aum's nuclear program) represent successful attempts by VNSAs to engage in complex engineering efforts. Table 4 encapsulates the major factors identified in each case study as being primarily responsible for the outcome of the complex engineering effort. The VNSAs under examination pursued very different types of technology as part of these efforts. Yet, while each case had some unique determinants of success, from the cases as a whole we can identify four key elements that in general might be expected to increase the probability of a VNSA being successful in a complex engineering endeavor.  1. Substantial investment of resources. The very nature of complex engineering efforts means that they will invariably require significant amounts of both human and financial resources to undertake. This is especially true when one considers the inevitable obstacles that will arise during any attempt to operationalize a new, complex process. Not only must a VNSA possess (or be able to acquire) high levels of resources, but it must be both willing and able to devote these resources to the complex engineering effort, most likely maintaining these levels over an extended period of time as the development process matures. In at least four of the five case studies of complex engineering efforts (Aum Shinrikyo, Los Zetas, FARC and Hamas), the VNSAs possessed large amounts of fungible resources that could be applied to the complex engineering effort without detracting significantly from other activities, and even in the case of the PIRA, the leadership was willing to devote a non-negligible proportion of its resources to mortar development for more than two decades. A corollary to this hypothesis is that a long-term commitment is needed for most complex engineering efforts to succeed.
2. Technical Expertise. As in the more general case of innovation by VNSAs, the transfer or development of the required technical knowledge and practical skills played a central role in determining outcomes in the case studies. 5 Whether by bringing in outside expertise (e.g., FARC and Los Zetas) or developing their own through trial-and-error (e.g., PIRA and Hamas), it is hypothesized that a VNSA complex engineering effort is unlikely to succeed without acquiring the appropriate amount of technical expertise for the effort at hand. In most respects, there is no place for amateurs in complex engineering efforts. The Aum Shinrikyo case exemplifies this-in the domain in which the group possessed expertise, namely chemical engineering, it was more successful, while in those areas where this expertise was lacking, namely nuclear physics and nuclear engineering, it failed miserably, despite the devotion of substantial resources and efforts in that direction. 3. Safe haven. As noted above, one feature shared by nearly all of the VNSAs studied was that they were able to pursue their complex engineering efforts over extended periods in circumstances where direct engagement with security forces was unlikely. They were able to engage in R&D in a relatively secure environment with relatively little operational risk. A plausible hypothesis is thus that some measure of safe haven is necessary for most VNSAs' complex engineering efforts to succeed.
4. Culture of learning. The last factor that seems to have played an important role in more than one case is the ability of the VNSA to identify the source of deficiencies in its efforts, and then to persevere until a solution to the problem is found and executed. This ties into the investment of resources in that it implies commitment to the effort over an extended period of time.
It is at this stage that reference to the A.Q. Khan case study can be made. The relevance of this case lies in how it demonstrates that VNSAs need not depend on state actors for even the most highly technical and difficult to obtain components and expertise required for complex engineering efforts. Driven by the opportunity for financial gain, A.Q. Khan stood at the head of an illicit non-state actor network that persisted for over fifteen years and spanned more than twenty countries around the world. Although the Khan network was provided with some cover by the Pakistani state, even when this diminished, the network endured despite extensive nonproliferation efforts by the major powers following the fall of the Soviet Union in the early 1990s. Two of the main reasons for the continued success of A.Q. Khan in providing nuclear equipment and expertise to a variety of customers (fortunately, none of them non-state actors) were the willingness of legitimate suppliers to look the other way in exchange for increased profit and the ability of the network to move further up the supply chain to obtain more basic components that were not controlled. Nor was the Khan case an anomaly. While it illustrates that an illicit trading network could exist for even the most dangerous and sophisticated technology, there are many other instances of non-state actor networks supplying dangerous materials for profit, including the longstanding arms smuggling networks of Viktor Bout and Monzer Al-Kasser and the biological agent exploits of Wouter Basson, the former head of the South African chemical and biological weapons programs, who also "went rogue" while enjoying the tacit protection of the state.

Future Research Directions and Policy Implications
The case studies have provided several insights into the decision, implementation and outcomes of complex engineering efforts as undertaken by VNSAs. The observation that we are able to discern several common elements-from similar decisional underpinnings to factors that facilitate implementation-across very different cases reflecting different time periods, geographic regions and motivations, indicates that VNSA complex engineering efforts might be shaped by similar dynamics and subject to a particular set of constraints. However, as noted in the introductory article to the special issue, the case studies represent only an exploratory investigation into the phenomenon. Although several hypotheses are suggested by the cases, these hypotheses require confirmation through more robust testing procedures before they can be fully utilized to shape policy and practice. In addition to identifying and investigating additional cases of successful complex engineering efforts by VNSAs, it will be necessary to explore multiple instances of failed attempts to engage in complex engineering. This would enable the use of several qualitative and quantitative methods, such as casecontrol sampling and Qualitative Comparative Analysis, 6 to determine the extent to which any of the hypothesized factors are necessary, sufficient or merely strongly correlated with particular outcomes and indicators.
With respect to how this study can help to inform counterterrorist and law enforcement policy and practice, if the above hypotheses are indeed confirmed by further investigation, many of them can be directly employed as observable indicators to show when a VNSA has the intent to engage in, or is already engaging in, complex engineering efforts. This would be useful for intelligence analysis at the operational level. For example, among the potential indicators that might prove most useful in detecting and interdicting VNSA complex engineering efforts are: (1) Changes in a VNSA's strategic or tactical environment for which no simple operational adaptation will compensate and where there are no readily available suppliers of the necessary technology; or (2) Attempts by a VNSA to recruit, hire, coerce or otherwise acquire technical expertise.
The factors that point to an increased (or decreased) likelihood of a VNSA engaging in, and especially succeeding in, complex engineering efforts can also inform strategic threat assessments, both of particular VNSAs and of classes of VNSAs such as transnational criminal organizations. Therefore, further research might confirm that the VNSAs that are most likely to pursue and succeed in complex engineering efforts are those which: (1) have a penchant for taking risks; (2) are willing and able to devote substantial resources to the effort for an extended period of time; (3) can conduct R&D through a specialized organ in a location of relative security; (4) tend to persevere in the face of setbacks; and (5) either already have, or can relatively easily acquire, the necessary expertise.
Overall, the current study has enriched our understanding of how and why VNSAs might engage in complex engineering efforts. It has shown that such endeavors will undoubtedly face a number of obstacles and requirements and thus hardly constitute faits accompli. Nonetheless, we must not underestimate the ability of VNSAs to accomplish remarkable feats of engineering in pursuit of their tactical and strategic goals. When organizational conditions are right, almost any technical task, even the most complex, become feasible for VNSAs.


REDUCING THE OPERATIONAL STOP TIME OF HAULLER KOMATSU HD465-7 BY USING THE SIX SIGMA’S APPROACH IN PT X

An operational stop time is a condition where heavy equipment is not working as usual. It is important to avoid this condition since excessive idling wastes an enormous amount of fuel and money. However, the operational stop time of a dump truck Hauller HD465-7 is 2.83 minutes, which is far above the normal standard. This project aims to optimize the improvement of an operational stop time by using a Six Sigma method with optimize plan selection. This will return the operational stop time to the standard range within 1.25 to 1.65 minutes. These steps of define, measure, analyze, improve, and control are applied to the standardization process according to the rules and criteria established by the Six Sigma. The result found that the Six Sigma ’s approach which was applied in PT X has reduced the cost from US$1,105,300 to US$963,000 every month. An improvement have been made to matching fleet by combining six fleet of dump trucks at driving speed of 22 km per hour and the average simulated haul distance was 2,000 meters.

INTRODUCTION
Six Sigma is a business strategic management which originally developed by Motorola in 1986 in order to enhance the quality of products through decreasing of product variations on manufacturing operations as they face compete in semiconductor industries. Through the application of the Six Sigma method, Motorolla has acknowledged an award of Malcolm Baldrige in 1988 as the first American's company which won its prestigious quality's award (Parsana et al. 2014). Six Sigma consists of a set of process where 99.9996 percent of resulted products are statistically expected to be free defects (3.4 ppm of level of reject or defect). Recently, the success processing rate of 99 percent is no longer being reminded and the world-class companies continue to enhance to provide both services and products perfectly to address zero defects. The main idea of Six Sigma is an approach to design the processes or to improve existing process to gain a very high capability/ability process in favor of near zero defects (Kwak et al. 2006). To illustrate why obtained level of 99 percent of quality is no longer enough, some facts are considered (McClusky, 2000). First, on mail delivery, reaching the quality of 99 percent meaning there are 10,000 mails are lost in every hour. Second, landing at airports for the quality of 99 percent meaning there are two unsafe landed aircraft in every hour. Third, medical surgical for the quality of 99 percent meaning there are 500 patients undergoing surgical errors in every week. Fourth, power plant operations for the quality of 99 percents implies seven hours blackout within a month.
According to these facts, by considering an obtained quality level for only 99 percent or 1 percent of defect levels on such cases in manufacturing industries or services can potentially lead to fatalities. Hence, for gaining the target of quality level of 99.9996 percent or free-defects, an organization requires both flexibility and discipline in solving problems using statistical approach rather than using simple intuition or by trial and error; wider usage of statistical treatments is one of the benefits of Six Sigma method (Pacheco, 2014). Application of Six Sigma's method is more valuable due to its contribution to the science and practice for particularly reduces waste and provides added values. Six Sigma allows users to identify waste and hidden costs, eliminates defects, increases profit margin, satisfies customers, encourages employee commitment and satisfaction as well as expands businesses (Patil et al, 2015).
The world-class companies within the Fortune 200's category such as Motorolla, GE, Bank of America, Honeywell, Boeing, Ford and other companies were using the Six Sigma programs to maximize their profits (Raisinghani, 2005 andKabir et al, 2013). Six Sigma as a management system is applied to ensure that efforts and critical opportunities for improvement are well developed through metric methodology and an applied level is inline with its business strategy. Six Sigma enables an organization to improve quality process by identifying and eliminating the causes of defects and error terms through minimizing variability in manufacturing and business processes (Mittal, 2014). The stages for improve process ability (process capability) regarding Six Sigma method are specifically allowing the standar steps such as define, measure, analyze, improve, and control for interlinked statistical tests. For a particular project within organization of applied of Six Sigma the stage is typically consists of a step-by-step requires for obtain measurable target values i.e. reduces cycle time, decreases air pollution, reduces costs, improves customer satisfaction, and increases profits (Mittal, 2014). It is inevitable, in order to gain benefits, as a results of Six Sigma's application in an organization or company, would require relatively high of initial investment, but might be offer benefits in long terms including cost savings, generated profits, improved consistency of quality processes, better employee performance, and better service quality and products. Those elements particularly would lead an organization or company to provide a higher customer satisfaction as well as to gain the ultimate goal of organization (Mittal, 2014). The existence of Six Sigma can be seen as a philosophy, business strategy, repair tool, and statistical measurement. Six Sigma is generally a management strategy, culture and change, and the need for organization to build as a whole into company's strategy plan. Six Sigma activities are focused on reducing the level of defect/failure of product or process (Taneja & Manchanda, 2013).
It is inevitable for an initial investment for application of Six Sigma as a tool requires high costs and probably only big companies be able to do so. Thus, training is required to implement and the objective is for everyone in organization or company to understand and involve. Application of Six Sigma's method requires higher investment than the lean (Anthony, 2011). The basic trainings of Six Sigma (white belt level) for one day would cover mapping process and description of various experimental designs such as design of experiment, hypothesis testing, and modeling process. A green belt training level has broader scope and longer duration; generally would conduct a week, the scope consists of a study of statistical analysis, statistical usage related to controlling process, and measurement systems and analysis. A higher one is black belt's level might be achieved through a completely intensive training course during one month, learn more in-depth analysis of variance (ANOVA), multivariate regression, and game theory (Raisinghani, 2005). Goal of the series of training and examinations is to make engineers to cope the green belt and black belt levels, enable them to work on innovative projects using Six Sigma's rule and standard, though it takes time to implement and higher initial investment is needed. The challenge is particularly how to keep small companies with limited capital expenditures can also be viewed as an interface with implemented methods in order to encourage their performance (Mittal, 2014). Six Sigma'method is used to obtain factual information regarding customer satisfaction applying such steps, i.e. define measure, analyze, improve, and control (DMAIC). Six Sigma as a measurement standard is referred to the theory of Carl Friedrich Gauss (1777-1855) who initially introduced the concept of normal distribution. Furthermore, Walter Shewhart found three sigmas as a measurement of variation in 1922, which stated that the process and intervention are needed if output goes beyond a limit (Raisinghani, 2005). There are two circumstances faced by manufacturing companies in terms of level of quality or high quality during 1980's period in the United States. The first one is an introduction of mass production of miniaturized electronics, transistor from radio to television, etc., which produce in large quantities for mass-market consumption. Secondly most related to opening of the United States market to foreign products particularly electronic devices made in Japan, which is the driving force to increase the quality of domestic products that was made in America. Both the quality and feature of products are two of the most advantages that made Japanese products are highly attractive to global consomers including American market (Raisinghani, 2005).
In order to response to Japanese foreign market penetration, an effort has been taken to a certain number of policy measures to improve the quality in the 1980's period. As the results, Ford Motor's automotive company introduced the quality system of zero defects, Boeing and Bell Telephone applied the concept of total quality management, Honeywell electronics and Fairchild developed the quality cycle concept that allows the average employee to engage more seriously by finding out what its customers need and enabling employees to deliver customer-oriented promises successfully (Raisinghani, 2005). The Nation has also seen the significant importance of the products and services. The Malcolm Baldrige National Quality Award (MBNQA) was established in 1987 by the U.S. Congress in an effort to promote quality improvement initiatives in U.S. businesses. The award program was named after former Secretary of Commerce, Malcolm Baldrige, and was designed and managed by the National Institute of Standards and Technology (NIST) with the help of private companies. Baldrige National Quality Improvement Act of 1987 (Public Law 100-107) signed into The Baldrige National Quality Award Program that was created by Congress through the Malcolm law by President Reagan on August 20, 1987.

METHODS
The method used to reduce the operational stop time of operation of Hauller Komatsu HD 465-7 is done with the series of Six Sigma standard procedures: (1) Define: define problem is the first phase of the Six Sigma improvement project. The main activities of this phase are to identify customers' needs in identifying their measurable improvement programme. (2) Measurement: the measurement in DMAIC is about understanding the current process, how the process is measured, and its baseline refers to a data-driven improvement cycle used for improving. (3) Analyze: the analyze phase is the beginning of the statistical analysis of the problem. The practical problem was created earlier. This phase statistically reviews the families of variation to determine which variables are the most significant contributors to the output. The statistical analysis is done beginning with a theory, null hypothesis. The analysis will fail to reject or reject the theory. (4) Improvement: The goal of the DMAIC Improve phase is to identify a solution to the problem that the project aims to address. This involves brainstorming potential solutions, selection solutions to test and evaluating the results of the implemented solutions. Often a pilot implementation is conducted prior to a full-scale rollout of improvements. It is important to include the people who are involved in performing the process in the first stage of improvement. Their input regarding potential improvements is critical, and this step should not be completed by the project team alone. In fact, it is wise to maintain communication with those who work on the process throughout any Six Sigma quality improvement project. (5) Control: The control phase is the conclusion of the team's journey. The primary objective of the DMAIC control phase is to ensure that the gains obtained during improve are maintained long after the project has ended. To that end, it is necessary to standardize and document procedures, make sure all employees are trained and communicate the project's results. In addition, the project team needs to create a plan for ongoing monitoring of the process and for reacting to any problems that arise.

Define
The earth-moving dump truck vehicle consists of five steps (Figure 1) An operational stop (wait) conditions creates underutilized trucks and look for opportunities to reduce wait times using the Six Sigma tool. Truck wait time occurs when the truck must wait to be loaded or to dump because of nonsynchronization in the haulage system. Operational stop times can be reduced by improving dump truck allocation and supervision and by dispatching systems. The average operational stop time of Komatsu HD 465-7 is 2.83 minutes, higher than 1.40 minutes meets the improvement target. The goals and targets examined here are those related to the cost quality and productivity (CQP) aspects with a breakthrough idea is to synchronize the improvement of a mixed fleet of Komatsu HD 465-7 and excavator Komatsu PC1250-7.

Measurement
As described above, operational stopped time is all the time that the truck was stopped during the entire haul cycle while it was operational. If the operational stopped time is high it would tend to suggest that there is a lot of time waiting at the loading tool. It could also reflect trucks left idling through breaks to keep the air conditioner or heater running. But the important point here is that it provides a clue as to where to look in the field if we want to reduce the idle time. If it turns out the operational stopped time is being incurred at the loading tool, we can then work out whether we are running too many trucks, whether the loading tool operator needs training, etc. Figure 2 shows the operational stopped times for Hauler Komatsu HD 465-7 based on actual field measurements. The Total Gage R&R contribution in the % Study Var column (% Tolerance, % Process) is 19.07 and the number of distinct categories is 7, indicated that the measurement system is acceptable.  The results show that the values of Z-ST and Z-Shift are 1.05 and 3.81, respectively; they indicate a lack of process control and lack technical knowledge and allowing for continual improvement stage as shown in Figure 4.

Analyze
Measurement results show that the potential factor input [F(x)] as measured this study effect on output (Y) of increases in the operational stop time is the speed for loaded and operational trucks, the number of haulage units, and the skill of the operator. Furthermore, a statistical analysis was conducted to determine the vital few significant factors out of a large potential factors being estimated. X1: speed vs operational stop time testing   P-Value > 0.05, "Accept Ho" (operator excavator skill, not vital factor)

Improvement
The concept of improving results and performance on a continual basis is universally hailed as a great idea. First off, in order to improve continuously, an organization or companies have to improve initially. Based on the test results for the analyze step, it can be seen that there are only two things which might be worth influencing an operational stop time: the speed for loaded and operational truck and the number of haulage units. Under the travel condition and moving at a constant speed, each vehicle is moving at 21 and 22 km/h, the combined of the six and seven vehicles. To obtain the most appropriate combination, improvement steps have been done using the design of experiment (DoE) techniques.
As shown by the value of P<5% for Main Effects and 2-Way Interaction, the speed as either a number of vehicles individually or in combination can potentially cause operational stopped time increases. Similarly as seen by the value of R-Sq (adj)>65% which indicates the average speeds and the number of vehicles are contributed for 99.43% of the operational stopped times. According to the optimal value, the optimal improvement result can be obtained by only combining a speed of 22 km/h and a number fleet of 6 units. In these combination exercises, the average operational stop time is 1.375 minutes, as shown in Figure 5.

Control
Six Sigma emphasizes the control phase because previous attempts at improving performance repeatly demonstrated that the whole process is complex and that hard-earned gains slip away if the process is left to itself. A well-designed process exhibits inherent self-control, while a poorly designed process requires frequent external control and adjustment to meet requirements. In order to apply the DMAIC tools developed, the organization or companies need to put this information into handbook of the standard of operational stopped time: 1.25 to 1.65 minutes are required for haul lengths of 2,000 meter, with a fleet of 6 dump trucks and a uniform velocity of 22 km/h.

RESULTS AND DISCUSSIONS
The purpose of the Six Sigma process is to identify and contain the vital views variables. In order to undertake hypothesis, a test is needed to express the research hypothesis as a null and alternative hypothesis. The null hypothesis and alternative hypothesis are statements regarding the differences or effects that occur in the population. Sample is used to test which statement (i.e., the null hypothesis or alternative hypothesis) is most likely (although technically, we test the evidence against the null hypothesis). The level of statistical significance is often expressed as the so-called p-value.
The cube plot shown in Figure Figure 7, the initial values of Z -ST and Z-shift are 1.05 and 3.81 (quadrant A), respectively, that has changed by improving steps. The new values of Z -ST and Z-shift are 4.29 and 1.12, respectively, (values of Z -ST -Z -LT ) indicate that operational stop time and their related quantity variables have been performed. Furthermore, the process of capability analysis entails comparing the performance of a process against its specifications. We say that a process is capable if, virtually, all of the possible variable values fall within the specification limits. Graphically, we assess process capability by plotting the process specification limits on a four block diagram as shown in Figure 8. If a value of capability process is within quadrant A, it means the problems is strongly related to poor technology and control aspects. The capability process that remains in quadrant B means that the technology is appropriate but less controlling. By contrast, an organization or company within quadrant C means that it lacks proper implementation of technologies but has appropriate controls to the user. The ideal one is given by the quadrant D (world class), where the capability process related to the technology implementation and control measures are fully integrated. Six Sigma as a management system can be easily implemented to raise productivity, increase the bottom line, improve quality and the customer experience, and increase financial savings.

CONCLUSIONS
Six Sigma has been successfully implemented to reduce operational stop times of dump truck Hauler HD 465-7 by 51% to average 1.38 from 2.83 minutes previously. This has successfully reduce its expenditure costs from US$ 1.105.300 to US$ 963.000 or provide savings and benefits about US$ 142.300 per month. Corrective action is taken to eliminate the causes of an existing operational stop time to address the problems identified. After trying a pair of possible combination of input variables and saw which combination performs the best, it was found out that a fleet of 6 dump trucks with a uniform velocity of 22 km/h for haul length of 2,000 meters would yielded a range of 1.25 to 1.65 minutes of the operational stop time. In the efforts of improvement, the values of Z -ST and Z-shift have been changed to 4.29 and 1.12 from 1.05 and 3.81, to show that the capability process has become better. It is noted that from the plotting that uses the four block diagram shows the values of Z short term (Z -ST ) and Z-shift are ≥4.5 and ≤1.5, indicating the project needs process improvement towards quadrant D, in terms of technology used and control measures. In addition to providing more financial savings, the success of a Six Sigma project can also be seen in the changes grade of values of Z -ST and Z-shift towards quadrant D (appropriate technology and control measures) which is considered under nearly ideal conditions.