we recognize our revenue according to the contract type . on a daily basis , we recognize service revenue over time for contracts that provide for specific time , material and equipment charges , which we bill periodically , ranging from weekly to monthly . we use the input method to faithfully depict revenue recognition , because each day of service provided represents value to the customer . the performance obligations in these contracts are satisfied , and revenue is recognized , as the work is performed . we have used the 29 expedient available to recognize revenue when the billing corresponds to the value realized by the customer where appropriate . we account for significant fixed-price contracts , mainly relating to our subsea products segment , and to a lesser extent in our subsea projects and advanced technologies segments , by recognizing revenue over time using an input , cost-to-cost measurement percentage-of-completion method . we use the input cost-to-cost method to faithfully depict revenue recognition . this commonly used method allows appropriate calculation of progress on our contracts . a performance obligation is satisfied as we create a product on behalf of the customer over the life of the contract . the remainder of our revenue is recognized at the point in time when control transfers to the customer , thus satisfying the performance obligation . we have elected to recognize the cost for freight and shipping as an expense when incurred . taxes assessed by a governmental authority that are both imposed on and concurrent with a specific revenue-producing transaction , and that are collected by us from customers , are excluded from revenue . in our service-based business lines , which principally charge on a day rate basis for services provided , there is no significant impact in the pattern of revenue and profit recognition as a result of implementation of asc 606. in our product-based business lines , there are impacts on the pattern of our revenue and profit recognition in our contracts using the percentage-of-completion method , as a result of the requirement to exclude uninstalled materials and significant inefficiencies from the measure of progress . this occurs in our subsea products segment . we apply judgment in the determination and allocation of transaction price to performance obligations , and the subsequent recognition of revenue , based on the facts and circumstances of each contract . we routinely review estimates related to our contracts and , where required , reflect revisions to profitability in earnings immediately . if an element of variable consideration has the potential for a significant future reversal of revenue , we will constrain that variable consideration to a level intended to remove the potential future reversal . if a current estimate of total contract cost indicates an ultimate loss on a contract , we recognize the projected loss in full when we determine it . in prior years , we have recorded adjustments to earnings as a result of revisions to contract estimates . we strive to estimate our contract costs and profitability accurately . however , there could be significant adjustments to overall contract costs in the future , due to changes in facts and circumstances . in general , our payment terms consist of those services billed regularly as provided and those products delivered at a point in time , which are invoiced after the performance obligation is satisfied . our product and service contracts with milestone payments due at agreed progress points during the contract are invoiced when those milestones are reached , which may differ from the timing of revenue recognition . our payment terms generally do not provide financing of contracts to customers , nor do we receive financing from customers as a result of these terms . property and equipment and long-lived intangible assets . we periodically and upon the occurrence of a triggering event review the realizability of our property and equipment and long-lived intangible assets to determine whether any events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable . for long-lived assets to be held and used , we base our evaluation on impairment indicators such as the nature of the assets , the future economic benefits of the assets , any historical or future profitability measurements and other external market conditions or factors that may be present . if such impairment indicators are present or other factors exist that indicate that the carrying amount of an asset may not be recoverable , we determine whether an impairment has occurred through the use of an undiscounted cash flows analysis of the asset at the lowest level for which identifiable cash flows exist . if an impairment has occurred , we recognize a loss for the difference between the carrying amount and the fair value of the asset . for assets held for sale or disposal , the fair value of the asset is measured using fair market value less cost to sell . assets are classified as held-for-sale when we have a plan for disposal of certain assets and those assets meet the held for sale criteria . 30 we charge the costs of repair and maintenance of property and equipment to operations as incurred , while we capitalize the costs of improvements that extend asset lives or functionality . goodwill . our goodwill is evaluated for impairment annually and whenever we identify certain triggering events or circumstances that would more likely than not reduce the fair value of a reporting unit below its carrying amount . story_separator_special_tag we added six , seven and six rovs to our fleet and retired ten , eight and 41 units during 2018 , 2017 and 2016 , respectively , resulting in a total of 275 work-class systems in our fleet at december 31 , 2018 . over the past three years , we retired a greater number of rovs than we have added due to market conditions and outlook . we previously had several deepwater vessels under long-term charter . the last of our long-term charters expired in march 2018. with the current market conditions , our philosophy is to attempt to charter vessels for specific projects on a back-to-back basis with the vessel owners . this generally minimizes our contract exposure by closely matching our obligations with our revenue . unless indicated otherwise , each of the chartered vessels discussed below is a deepwater multiservice subsea support vessel outfitted with two of our high-specification work-class rovs . in 2012 , we moved the chartered vessel ocean intervention iii to angola and also chartered the bourbon oceanteam 101 to work on a three-year field support vessel services contract for a unit of bp plc . we had extended the charter of the bourbon oceanteam 101 to january 2017. however , in early 2016 , the customer exercised its right , under the field support vessel services contract , to terminate its use of the bourbon oceanteam 101 at the end of may 2016. under the terms of the contract , the costs incurred by us associated with the early release and demobilization of the vessel were reimbursed by the customer . following the release of the vessel , we redelivered it to the vessel supplier . the charter for the ocean intervention iii expired at the end of july 2017. under the field support vessel services contract , which was extended through january 2022 , we are continuing to supply project management and engineering services . we also provide rov tooling and asset integrity services as requested by the customer . chartered vessels and barges are provided to the customer upon request . in march 2013 , we commenced a five-year bareboat charter for a jones act-compliant multiservice support vessel , the ocean alliance , we have been using in the u.s. gulf of mexico . in january 2015 , we commenced a two-year contract with a customer for the use of the ocean alliance , which expired in january 2017. we returned the ocean alliance to the vessel owner in the first quarter of 2018 and continue to market the vessel , now renamed the cade candies , for spot market work in the u.s. gulf of mexico on a back-to-back basis with the owner . in december 2013 , we commenced a three-year charter for the normand flower , a multiservice subsea marine support vessel . we made modifications to the vessel and used the vessel in the u.s. gulf of mexico to perform inspection , maintenance and repair projects and hardware installations . in december 2016 , we declined our option to extend the charter and the vessel was released . in november 2015 , we commenced a two-year charter for the use of the island pride , a multiservice subsea marine support vessel . we used the vessel under a two-year contract to provide field support services off the coast of india for an oil and gas customer based in india . in 34 november 2017 , that field services contract expired and we declined our option to extend the vessel charter . we also charter or lease vessels on a short-term basis as necessary to augment our fleet . during the third quarter of 2013 , we signed an agreement with a shipyard for the construction of a subsea support vessel , to be named the ocean evolution . we expect to take delivery in the first quarter and place the vessel into service in the second quarter of 2019. we intend for the vessel to be u.s. flagged and documented with a coastwise endorsement by the u.s. coast guard . the vessel has an overall length of 353 feet , a class 2 dynamic positioning system , accommodations for 110 personnel , a helideck , a 250-ton active heave-compensated crane , a working moonpool , and two of our high specification 4,000 meter work-class rovs . the vessel is also equipped with a satellite communications system capable of transmitting streaming video for real-time work observation by shore personnel . we anticipate the vessel will be used to augment our ability to provide subsea intervention services in the u.s. gulf of mexico . these services are required to perform inspection , maintenance and repair projects and hardware installations . our principal source of cash from operating activities is our net income ( loss ) , adjusted for the non-cash expenses of depreciation and amortization , deferred income taxes and noncash compensation under our restricted stock plans . our $ 37 million , $ 136 million and $ 339 million of cash provided from operating activities in 2018 , 2017 and 2016 , respectively , were affected by cash increases ( decreases ) of : ( 1 ) $ ( 87 ) million , $ 13 million and $ 123 million , respectively , of changes in accounts receivable ; ( 2 ) $ ( 12 ) million , $ 66 million and $ 18 million , respectively , of changes in inventory ; and ( 3 ) $ 29 million , $ ( 76 ) million and $ ( 115 ) million , respectively , of changes in accounts payable and accrued liabilities . the decrease in cash related to accounts receivable in 2018 reflected higher business levels in the fourth quarter of 2018 , as compared to the fourth quarter of 2017 , along with timing of customer payments . the increase in cash related to changes in current liabilities in 2018 reflected timing of

liquidity and capital resources we consider our liquidity and capital resources adequate to support our operations and growth initiatives . at december 31 , 2018 , we had working capital of $ 750 million , including cash and cash equivalents of $ 354 million . additionally , we had $ 500 million available through our revolving credit facility under a credit agreement further described below . in november 2014 , we completed the public offering of $ 500 million aggregate principal amount of 4.650 % senior notes due 2024 ( the `` 2024 senior notes '' ) . we pay interest on the 2024 senior notes on may 15 and november 15 of each year . the 2024 senior notes are scheduled to mature on november 15 , 2024. in february 2018 , we completed the public offering of $ 300 million aggregate principal amount of 6.000 % senior notes due 2028 ( the `` 2028 senior notes '' ) . we pay interest on the 2028 senior notes on february 1 and august 1 of each year . the 2028 senior notes are scheduled to mature on february 1 , 2028. we may redeem some or all of the 2024 senior notes and the 2028 senior notes ( collectively , the `` senior notes '' ) at specified redemption prices . we used the net proceeds from the 2028 senior notes to repay our term loan indebtedness described further below .


 Write a concise suspicious activity report of the following text delimited by triple backquotes. Return your response as a formal report which covers the key points highlighting the location,dates,entity names and account holder information in chronological order of the text.
     ```liquidity and capital resources we consider our liquidity and capital resources adequate to support our operations and growth initiatives . at december 31 , 2018 , we had working capital of $ 750 million , including cash and cash equivalents of $ 354 million . additionally , we had $ 500 million available through our revolving credit facility under a credit agreement further described below . in november 2014 , we completed the public offering of $ 500 million aggregate principal amount of 4.650 % senior notes due 2024 ( the `` 2024 senior notes '' ) . we pay interest on the 2024 senior notes on may 15 and november 15 of each year . the 2024 senior notes are scheduled to mature on november 15 , 2024. in february 2018 , we completed the public offering of $ 300 million aggregate principal amount of 6.000 % senior notes due 2028 ( the `` 2028 senior notes '' ) . we pay interest on the 2028 senior notes on february 1 and august 1 of each year . the 2028 senior notes are scheduled to mature on february 1 , 2028. we may redeem some or all of the 2024 senior notes and the 2028 senior notes ( collectively , the `` senior notes '' ) at specified redemption prices . we used the net proceeds from the 2028 senior notes to repay our term loan indebtedness described further below .
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 Suspicious Activity Report : we recognize our revenue according to the contract type . on a daily basis , we recognize service revenue over time for contracts that provide for specific time , material and equipment charges , which we bill periodically , ranging from weekly to monthly . we use the input method to faithfully depict revenue recognition , because each day of service provided represents value to the customer . the performance obligations in these contracts are satisfied , and revenue is recognized , as the work is performed . we have used the 29 expedient available to recognize revenue when the billing corresponds to the value realized by the customer where appropriate . we account for significant fixed-price contracts , mainly relating to our subsea products segment , and to a lesser extent in our subsea projects and advanced technologies segments , by recognizing revenue over time using an input , cost-to-cost measurement percentage-of-completion method . we use the input cost-to-cost method to faithfully depict revenue recognition . this commonly used method allows appropriate calculation of progress on our contracts . a performance obligation is satisfied as we create a product on behalf of the customer over the life of the contract . the remainder of our revenue is recognized at the point in time when control transfers to the customer , thus satisfying the performance obligation . we have elected to recognize the cost for freight and shipping as an expense when incurred . taxes assessed by a governmental authority that are both imposed on and concurrent with a specific revenue-producing transaction , and that are collected by us from customers , are excluded from revenue . in our service-based business lines , which principally charge on a day rate basis for services provided , there is no significant impact in the pattern of revenue and profit recognition as a result of implementation of asc 606. in our product-based business lines , there are impacts on the pattern of our revenue and profit recognition in our contracts using the percentage-of-completion method , as a result of the requirement to exclude uninstalled materials and significant inefficiencies from the measure of progress . this occurs in our subsea products segment . we apply judgment in the determination and allocation of transaction price to performance obligations , and the subsequent recognition of revenue , based on the facts and circumstances of each contract . we routinely review estimates related to our contracts and , where required , reflect revisions to profitability in earnings immediately . if an element of variable consideration has the potential for a significant future reversal of revenue , we will constrain that variable consideration to a level intended to remove the potential future reversal . if a current estimate of total contract cost indicates an ultimate loss on a contract , we recognize the projected loss in full when we determine it . in prior years , we have recorded adjustments to earnings as a result of revisions to contract estimates . we strive to estimate our contract costs and profitability accurately . however , there could be significant adjustments to overall contract costs in the future , due to changes in facts and circumstances . in general , our payment terms consist of those services billed regularly as provided and those products delivered at a point in time , which are invoiced after the performance obligation is satisfied . our product and service contracts with milestone payments due at agreed progress points during the contract are invoiced when those milestones are reached , which may differ from the timing of revenue recognition . our payment terms generally do not provide financing of contracts to customers , nor do we receive financing from customers as a result of these terms . property and equipment and long-lived intangible assets . we periodically and upon the occurrence of a triggering event review the realizability of our property and equipment and long-lived intangible assets to determine whether any events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable . for long-lived assets to be held and used , we base our evaluation on impairment indicators such as the nature of the assets , the future economic benefits of the assets , any historical or future profitability measurements and other external market conditions or factors that may be present . if such impairment indicators are present or other factors exist that indicate that the carrying amount of an asset may not be recoverable , we determine whether an impairment has occurred through the use of an undiscounted cash flows analysis of the asset at the lowest level for which identifiable cash flows exist . if an impairment has occurred , we recognize a loss for the difference between the carrying amount and the fair value of the asset . for assets held for sale or disposal , the fair value of the asset is measured using fair market value less cost to sell . assets are classified as held-for-sale when we have a plan for disposal of certain assets and those assets meet the held for sale criteria . 30 we charge the costs of repair and maintenance of property and equipment to operations as incurred , while we capitalize the costs of improvements that extend asset lives or functionality . goodwill . our goodwill is evaluated for impairment annually and whenever we identify certain triggering events or circumstances that would more likely than not reduce the fair value of a reporting unit below its carrying amount . story_separator_special_tag we added six , seven and six rovs to our fleet and retired ten , eight and 41 units during 2018 , 2017 and 2016 , respectively , resulting in a total of 275 work-class systems in our fleet at december 31 , 2018 . over the past three years , we retired a greater number of rovs than we have added due to market conditions and outlook . we previously had several deepwater vessels under long-term charter . the last of our long-term charters expired in march 2018. with the current market conditions , our philosophy is to attempt to charter vessels for specific projects on a back-to-back basis with the vessel owners . this generally minimizes our contract exposure by closely matching our obligations with our revenue . unless indicated otherwise , each of the chartered vessels discussed below is a deepwater multiservice subsea support vessel outfitted with two of our high-specification work-class rovs . in 2012 , we moved the chartered vessel ocean intervention iii to angola and also chartered the bourbon oceanteam 101 to work on a three-year field support vessel services contract for a unit of bp plc . we had extended the charter of the bourbon oceanteam 101 to january 2017. however , in early 2016 , the customer exercised its right , under the field support vessel services contract , to terminate its use of the bourbon oceanteam 101 at the end of may 2016. under the terms of the contract , the costs incurred by us associated with the early release and demobilization of the vessel were reimbursed by the customer . following the release of the vessel , we redelivered it to the vessel supplier . the charter for the ocean intervention iii expired at the end of july 2017. under the field support vessel services contract , which was extended through january 2022 , we are continuing to supply project management and engineering services . we also provide rov tooling and asset integrity services as requested by the customer . chartered vessels and barges are provided to the customer upon request . in march 2013 , we commenced a five-year bareboat charter for a jones act-compliant multiservice support vessel , the ocean alliance , we have been using in the u.s. gulf of mexico . in january 2015 , we commenced a two-year contract with a customer for the use of the ocean alliance , which expired in january 2017. we returned the ocean alliance to the vessel owner in the first quarter of 2018 and continue to market the vessel , now renamed the cade candies , for spot market work in the u.s. gulf of mexico on a back-to-back basis with the owner . in december 2013 , we commenced a three-year charter for the normand flower , a multiservice subsea marine support vessel . we made modifications to the vessel and used the vessel in the u.s. gulf of mexico to perform inspection , maintenance and repair projects and hardware installations . in december 2016 , we declined our option to extend the charter and the vessel was released . in november 2015 , we commenced a two-year charter for the use of the island pride , a multiservice subsea marine support vessel . we used the vessel under a two-year contract to provide field support services off the coast of india for an oil and gas customer based in india . in 34 november 2017 , that field services contract expired and we declined our option to extend the vessel charter . we also charter or lease vessels on a short-term basis as necessary to augment our fleet . during the third quarter of 2013 , we signed an agreement with a shipyard for the construction of a subsea support vessel , to be named the ocean evolution . we expect to take delivery in the first quarter and place the vessel into service in the second quarter of 2019. we intend for the vessel to be u.s. flagged and documented with a coastwise endorsement by the u.s. coast guard . the vessel has an overall length of 353 feet , a class 2 dynamic positioning system , accommodations for 110 personnel , a helideck , a 250-ton active heave-compensated crane , a working moonpool , and two of our high specification 4,000 meter work-class rovs . the vessel is also equipped with a satellite communications system capable of transmitting streaming video for real-time work observation by shore personnel . we anticipate the vessel will be used to augment our ability to provide subsea intervention services in the u.s. gulf of mexico . these services are required to perform inspection , maintenance and repair projects and hardware installations . our principal source of cash from operating activities is our net income ( loss ) , adjusted for the non-cash expenses of depreciation and amortization , deferred income taxes and noncash compensation under our restricted stock plans . our $ 37 million , $ 136 million and $ 339 million of cash provided from operating activities in 2018 , 2017 and 2016 , respectively , were affected by cash increases ( decreases ) of : ( 1 ) $ ( 87 ) million , $ 13 million and $ 123 million , respectively , of changes in accounts receivable ; ( 2 ) $ ( 12 ) million , $ 66 million and $ 18 million , respectively , of changes in inventory ; and ( 3 ) $ 29 million , $ ( 76 ) million and $ ( 115 ) million , respectively , of changes in accounts payable and accrued liabilities . the decrease in cash related to accounts receivable in 2018 reflected higher business levels in the fourth quarter of 2018 , as compared to the fourth quarter of 2017 , along with timing of customer payments . the increase in cash related to changes in current liabilities in 2018 reflected timing of

