Citation Context

...perspace.sPCA is a useful methodsfor quantifying the correlation (or lack thereof) amongst the system outputs and representing the resultingssystem output tradeoff hyperspace in a reduced-order space =-=[86]-=-.sThis representation enables the mostsimportant system output tradeoffs to be readily identified, as will be demonstrated hereafter.sIn this analysis, PCA was specifically used to analyze the data co...

Citation Context

...haracteristic of the DBDsframework is that candidatesalternatives, or products aresranked using expected utilitysand therein optimized tosdetermine the highest valuesalternative, or candidatesproduct =-=[3,4]-=-.sAn overviewsof the DBF framework issprovided in Figure 2-2s(adapted from Ref. [2]).sAs seen in Figure 2-2, the inputs to the framework are the system configuration (e.g., a product) along withsthe e...

Citation Context

...pectively.sThe two change dimensions in the taxonomy create four potentialscategories of system design and/or operational change; these are depicted in Figure 4-4 and adapted fromsHenderson and Clark =-=[41]-=-.sThe first category, No Change, uses the current or existing technology (design)sand ConOps (operation) for a system; therefore, this category is often considered the datum, or baselinessystem state....

Citation Context

...represent value on a cardinal measurement scale,swhich allows relative differences in value to be quantified, something not possible with ordinal values(preference) functions such as Expected Utility =-=[3,4,52,56]-=-.sThere are several benefits to having a cardinalsvalue function, including the ability to create a value-ranked ordering of system options (e.g., proposedschanges), for a given λ-Set, and this may en...

Citation Context

...aluates engineeringsproducts, that is, tangible systems or objects that have a corresponding market and ensuing demand andssupply such that revenue is generated from the product given a sell price, P =-=[2]-=-.sThe DBD frameworkstherefore implicitly considers the tradeoffs associated with engineering products along with including thesrelevant needs of the product developers, manufacturers, and customer mar...

Citation Context

...haracteristic of the DBDsframework is that candidatesalternatives, or products aresranked using expected utilitysand therein optimized tosdetermine the highest valuesalternative, or candidatesproduct =-=[3,4]-=-.sAn overviewsof the DBF framework issprovided in Figure 2-2s(adapted from Ref. [2]).sAs seen in Figure 2-2, the inputs to the framework are the system configuration (e.g., a product) along withsthe e...

Citation Context

...evant to note that MATE was first developed in 2002sand since then a number of adaptations of the MATE process have been developed and applied and thesesinclude: MATE for Changeability (Dynamic MATE) =-=[7]-=-; MATE for Systems-of-Systems [8,9]; MATE forsFlexibility [10,11]; and MATE for Survivability [12].sA corresponding overview of the core of the MATEsprocess and thereby any subsequent version of MATE ...

Citation Context

...one supravalue function, however, the major disadvantage of the supra-objective function approach for facilitatingsstakeholder alignment is best reflected through Arrow’s “General Possibility Theory” =-=[63]-=-.sThe GeneralsPossibility Theory, in part, concludes that aggregating multiple stakeholder preferences (e.g., via a supraobjective function) cannot be done without forcing stakeholders to compromise t...

Citation Context

...ibutes, asUtility, u Demand,sq(a,P,t)sCorporatesPreferencessChoose x tosmax, usFigure 2-2.sDecision-based Design Framework.s28s© 2012 Massachusetts Institute of Technology. All rights reserved.sspace =-=[5,6]-=-.sHere, utility aggregates the attributes, or tradeoff dimensions of interest for a given design thatsare beneficial to the relevant stakeholders and positions them relative to the cost(s) of the desi...

Citation Context

... MATE process have been developed and applied and thesesinclude: MATE for Changeability (Dynamic MATE) [7]; MATE for Systems-of-Systems [8,9]; MATE forsFlexibility [10,11]; and MATE for Survivability =-=[12]-=-.sA corresponding overview of the core of the MATEsprocess and thereby any subsequent version of MATE is provided in Figure 2-3 (adapted from Ref. [6]).sAs seen in Figure 2-3, thescore of the MATE pro...

Citation Context

...of change propagationsframeworks is their reliance on Design Structure Matrices (DSM’s) in order to characterize thesinterdependencies of a system’s components and/or information flows (refer to Ref. =-=[16]-=- for a descriptionsof DSM’s).sThrough characterizing a system in a DSM, changes in the system can be identified, tracked,sand quantified, forming the basis for deriving measures of the type and magnit...

Citation Context

...is fielded and two common hazard and risk analysissframeworks are Failure Modes, Effect, and Critical Analysis (FMECA) [17] and Systems-Theoretic AccidentsModeling and Process (STAMP) Hazard Analysis =-=[18]-=-.sThe hazard and risk framework discussed hereafter isssuggested as an improvement upon the STAMP hazard analysis and was developed by Marais [19].sThissframework is shown in Figure 2-5 (image source:...

Citation Context

...e employment of three classes ofsshared subsystem resources, and hence enabling technologies in fractionated spacecraft: (1) communication,scomputer system, and command & data handling (Comm_CS_C&DH) =-=[119]-=-; (2) attitude determinationssystem and guidance navigation system (ADS_GNS) [124,125]; and (3) power generation and storages(Power) [111,126].sGiven the current and near-term envisioned state of the ...

Citation Context

...ibutes, asUtility, u Demand,sq(a,P,t)sCorporatesPreferencessChoose x tosmax, usFigure 2-2.sDecision-based Design Framework.s28s© 2012 Massachusetts Institute of Technology. All rights reserved.sspace =-=[5,6]-=-.sHere, utility aggregates the attributes, or tradeoff dimensions of interest for a given design thatsare beneficial to the relevant stakeholders and positions them relative to the cost(s) of the desi...

Citation Context

...candidate system designs orsconfigurations.sOne example of asMAMCA framework is that developedsby Macharis et al., which is shown insFigure 2-6 and used as a representativesexample of such frameworks =-=[20]-=-.sMacharis’s MAMCA framework begins with a stakeholder analysis.sThis analysis is used to identify thesrelevant stakeholders given the system of interest and then to use their needs as the criteria ba...

Citation Context

... then a number of adaptations of the MATE process have been developed and applied and thesesinclude: MATE for Changeability (Dynamic MATE) [7]; MATE for Systems-of-Systems [8,9]; MATE forsFlexibility =-=[10,11]-=-; and MATE for Survivability [12].sA corresponding overview of the core of the MATEsprocess and thereby any subsequent version of MATE is provided in Figure 2-3 (adapted from Ref. [6]).sAs seen in Fig...

Citation Context

...ential valuation approach for use in the framework.sCBA is a prescriptivesvaluation methodology that quantifies value through the net benefits yielded by a system relative to itssrespective net costs =-=[53,54]-=-.sCBA therefore interprets value as benefit less cost mapped to a commonsmeasurement scale.sThus, CBA serves as a useful value-centric tool for cardinally weighting the positivesand negative effects o...

Citation Context

...ARPA) System Future, Fast,sFlexible, Fractionated, Free-Flying United by Information Exchange (F6) Program was initiated in 2007s125s© 2012 Massachusetts Institute of Technology. All rights reserved.s=-=[118,128]-=-12. During the intervening three years, under the broad programmatic umbrella of the System F6sprogram, a diverse set of conceptual fractionated spacecraft studies were undertaken [129–131].sGiven the...

Citation Context

...k-σsTechnology Risk Model to generate distributions of technology performance gains and losses as asfunction of the technology’s TRL; a good example of one of these distributions can be found in Ref.s=-=[30]-=- and is shown in Figure 3-3.sThese distributions assume that performance probabilisticallys39s© 2012 Massachusetts Institute of Technology. All rights reserved.sdegrades with TRL and aressubsequently ...

Citation Context

...then it is a headwind or a tailwind,srespectively.sAircraft will produce contrails if they flysin a contrail region and these regions are formulatedsusing the Schmidt-Appleman criterion for contrailss=-=[83]-=-.sIn the cruise environment, the weather data atsaltitude are populated by the Rapid Update Cycles(RUC) weather model [84].sAnd, lastly, thesturbulence severity regions in Figure 6-4 aresapproximated ...

Citation Context

...ckground 8.1. Fractionated spacecraft consist of physically independent structures, referred to as modules, where eachsmodule may not have the same subsystem/hardware composition as the other modules =-=[110,111]-=-.sOnorbit, modules maintain a cluster or formation flying configuration and they wirelessly interact (collaborate)sto share certain subsystem resources.sFigures8-1 conceptual depicts a fractionatedssp...

Citation Context

...sThis ability to decouple subsystems and payloads may allow individualsmodules to be less massive and smaller than a comparable monolith, or yield other benefits extensible to asspecific mission area =-=[111,116,117]-=-.sIn recent years, fractionated spacecraft have gained support because ofstheir potential to offer improved lifecycle performance, or value relative to comparable monoliths.sIt isssuggested that distr...

Citation Context

...ential valuation approach for use in the framework.sCBA is a prescriptivesvaluation methodology that quantifies value through the net benefits yielded by a system relative to itssrespective net costs =-=[53,54]-=-.sCBA therefore interprets value as benefit less cost mapped to a commonsmeasurement scale.sThus, CBA serves as a useful value-centric tool for cardinally weighting the positivesand negative effects o...

Citation Context

... several unique versions of CPA frameworks, the Change Prediction Method (CPM) fromsClarkson et al. shown in Figure 2-4 is discussed as a representative example of such frameworks (imagessource: Ref. =-=[13]-=-).sClarkson’s CPM framework can be parsed into three components: method inputs,smethod execution, and method outputs.sThe required inputs to this method are the product, or system ofsto be analyzed as...

Citation Context

... developed in 2002sand since then a number of adaptations of the MATE process have been developed and applied and thesesinclude: MATE for Changeability (Dynamic MATE) [7]; MATE for Systems-of-Systems =-=[8,9]-=-; MATE forsFlexibility [10,11]; and MATE for Survivability [12].sA corresponding overview of the core of the MATEsprocess and thereby any subsequent version of MATE is provided in Figure 2-3 (adapted ...

Citation Context

... developed in 2002sand since then a number of adaptations of the MATE process have been developed and applied and thesesinclude: MATE for Changeability (Dynamic MATE) [7]; MATE for Systems-of-Systems =-=[8,9]-=-; MATE forsFlexibility [10,11]; and MATE for Survivability [12].sA corresponding overview of the core of the MATEsprocess and thereby any subsequent version of MATE is provided in Figure 2-3 (adapted ...

Citation Context

...t study from Kroo was published in 2009 and is unique because of its inclusion of asclimate impact model, which quantifies the global temperature response from aircraft engine emissions andscontrails =-=[73]-=-.sThe tradeoff dimensions in this study were again optimized using PASS and included metricsssuch as global temperature change, cost, fuel burn, and NOx emissions.sWaitz led MIT’s most focused researc...

Citation Context

...AccidentsModeling and Process (STAMP) Hazard Analysis [18].sThe hazard and risk framework discussed hereafter isssuggested as an improvement upon the STAMP hazard analysis and was developed by Marais =-=[19]-=-.sThissframework is shown in Figure 2-5 (image source: Ref. [19]).sFigure 2-4.sChange Prediction Method Framework.s31s© 2012 Massachusetts Institute of Technology. All rights reserved.sMarais’s hazard...

Citation Context

... RNAV performance, RNAV-X implies that ansaircraft will not deviate from its flight path laterally and horizontally bysX nm for 95% of the total flight time; the lateral buffer is shown insFigure 7-1 =-=[89]-=-.sIntuitively, lower -X values will require higher RNAVsprecision.sRNP performance is analogous to RNAV performance insterms requirements for navigating a given airspace.sFor example, RNP1 is often us...

Citation Context

...ckground 8.1. Fractionated spacecraft consist of physically independent structures, referred to as modules, where eachsmodule may not have the same subsystem/hardware composition as the other modules =-=[110,111]-=-.sOnorbit, modules maintain a cluster or formation flying configuration and they wirelessly interact (collaborate)sto share certain subsystem resources.sFigures8-1 conceptual depicts a fractionatedssp...

Citation Context

...deoffs associated with change, or innovation in systems.sThe relevant, formal approaches in thesliterature are briefly discussed hereafter.s1. Technology Metric Assessment and Tracking (TMAT) Process =-=[24]-=-.sThe TMAT processsis used to evaluate the tradeoffs associated with inserting new technologies in systems and the fivesmajor steps of the TMAT process include:s1. Technology metric (i.e., measure of ...

Citation Context

...abilities of the valuation methods.sRoss et al. discuss prominent valuationsmethods in order to provide guidance for practitioners in choosing the most appropriate method for asparticular application =-=[52]-=-.sWhile valuation methods are used in numerous applications, quantifying humanspreferences is a challenging task, so many of the valuation methods can lead to preference structures withsconsiderable u...

Citation Context

...s, or relative preference weightingssamongst the costs and benefits.sThe general form of an additive cost-benefit function with uniformspreference weightings is given in Equation 3 (adapted from Ref. =-=[55]-=-).sEquation 3s!sValue = P Y = "i # Yi t( )( ) i=1 m $ 1+ r( )t%t $sIn Equation 3, Value is the benefit of a system less it respective cost.sThe discount rate, r is the rate ofsreturn on future investm...

Citation Context

... then a number of adaptations of the MATE process have been developed and applied and thesesinclude: MATE for Changeability (Dynamic MATE) [7]; MATE for Systems-of-Systems [8,9]; MATE forsFlexibility =-=[10,11]-=-; and MATE for Survivability [12].sA corresponding overview of the core of the MATEsprocess and thereby any subsequent version of MATE is provided in Figure 2-3 (adapted from Ref. [6]).sAs seen in Fig...

Citation Context

...mizer to balance performance gains with technology risksdue to increasing innovation [30–33],sand one of these works does so while also allowing the typesof technologies available to change over time =-=[35]-=-.sFor those works using the K-σ Technology RisksModel that assume technology performance is constant, an implicit assumption is therefore that thesdesired level of technology performance is always ava...

Citation Context

...of 2.2 people per household; and (4) that airports amortize the cost ofssoundproofing homes on an annual basis.sFor the airline, λNoise is based on current noise levies at airports insEurope and Asia =-=[108]-=-; these levies are transformed to a person-DNL cost basis assuming a charge of $0.41sper person-DNL exposed to DNL ≥ 65dB.sLastly, λNoise for the community is based on recommendationssfrom the Aviatio...

Citation Context

...sThis ability to decouple subsystems and payloads may allow individualsmodules to be less massive and smaller than a comparable monolith, or yield other benefits extensible to asspecific mission area =-=[111,116,117]-=-.sIn recent years, fractionated spacecraft have gained support because ofstheir potential to offer improved lifecycle performance, or value relative to comparable monoliths.sIt isssuggested that distr...

Citation Context

...eholders and theirsrespective value through the figures of merit.sThis method was applied to NASA’s NextsGeneration Launch Technology project in Ref. [26].s4. Technology Performance Risk Index (TPRI) =-=[27]-=-.sTPRI tracks technology readinesssthroughout a lifecycle and is comparable to the TRL scale and can thus be used to analyze thesimpact of innovation in a system’s design and/or operation.sTPRI specif...

Citation Context

...e instances of aircraft collidingswith the ground or water under full pilot control and these were the leading cause of aviation accidents andsfatalities in the world at least through the late 1990’s =-=[42,43]-=-.sReducing CFIT accidents was addressedsthrough innovation in aircraft technology, which has greatly reduced the number of CFIT incidentssobserved in the present day [42].sIn terms of the Change Taxon...

Citation Context

... literature investigating environmental andsperformance tradeoffs for aircraft cruise operations for the Climate Compatible Air Transport (CATS)sSystem and Aviation Integrated Modelling (AIM) Project =-=[76,77]-=-.sThe work on the CATS System wasspublished in 2009 and it specifically analyzed aircraft cruise operations by considering the tradeoffssamongst: engine technology (capability), contrail formation, pe...

Citation Context

...in Figure 6-11.sWhile a contrail tax may be one potential future regulation in aviation, there is also presently an increasingsemphasis on regulating aircraft emissions through a tax on CO2 emissions =-=[87]-=-; currently, discussions arescentered on what carbon-based metric should be usedsto quantify and thereby regulate carbon emissions.sOnespotential option for regulating carbon emissions is tostax these...

Citation Context

...rks solelysfocused on noise reduction as the measure of success for a given approach procedure, resulting in insightfulsnoise tradeoff quantifications associated with changing procedures via RNAV/RNP =-=[94]-=-.sThe second ofsthese works developed a tool called NOISHHH, which optimizes aircraft approach trajectories with a multiobjective function comprised of flight time, number of awakenings (noise proxy),...

Citation Context

... aircraftstrajectory optimization model, was developed to optimize aircraft cruise phases in terms of altitude whilesminimizing their ecological impact as measured through CO2 emissions and contrails =-=[96]-=-; the ETPM cansalso optimize the climb and descent phases of an aircraft’s respective operation.sIn the relevant literature, there are several works that provide approaches and methods to resolvescomp...

Citation Context

...to analyze a system in order tosmitigate residual risks in that system before it is fielded and two common hazard and risk analysissframeworks are Failure Modes, Effect, and Critical Analysis (FMECA) =-=[17]-=- and Systems-Theoretic AccidentsModeling and Process (STAMP) Hazard Analysis [18].sThe hazard and risk framework discussed hereafter isssuggested as an improvement upon the STAMP hazard analysis and w...

Citation Context

...arity, the innovation profile in Figure 3-2 has probability distributions along it thatsdefine confidence regions in technology improvement over time.s2. Cardinal Technology Readiness Scale Valuation =-=[25]-=-.sThis approach to analyzing systemsssimply maps the impact of innovation in system design and/or operation to a continuoussTechnology Readiness Level (TRL) scale, thereby providing technology readine...

Citation Context

...ular.s3. Internet-Accessible Technology Risk Assessment Collaborative System (ITRACS) andsFramework for Advanced Systems Tradeoffs using Probabilistic Analysis of Conceptssand Technologies (FASTPACT) =-=[26]-=-.sThe FASTPACT approach is used to quantify the impactsof new technology (or technology portfolios) on a program’s figures of merit based on informationsfrom applying ITRACS, which solicits expert opi...

Citation Context

...m due to the technology.sThis approach was applied to asgeneric weapon system in Ref. [27].s38s© 2012 Massachusetts Institute of Technology. All rights reserved.s5. Developmental Maturity Index (DMI) =-=[28]-=-.sThe DMI is suggested as being an improvementsto the TRL scale for capturing technology maturity and therein the impact of changes, orsinnovation in a system’s design and/or operation.sThe DMI is qua...

Citation Context

...e instances of aircraft collidingswith the ground or water under full pilot control and these were the leading cause of aviation accidents andsfatalities in the world at least through the late 1990’s =-=[42,43]-=-.sReducing CFIT accidents was addressedsthrough innovation in aircraft technology, which has greatly reduced the number of CFIT incidentssobserved in the present day [42].sIn terms of the Change Taxon...

Citation Context

...global communication network to supportsinterplanetary space missions as well as to perform astronomical observations of the solar system andsbeyond.sThe history of the DSN is well summarized in Ref. =-=[44,45]-=- and the origins of the DSN programsbegan around 1958.sBefore the DSN was officially sanctioned, the U.S. Army and Jet PropulsionsLaboratory (JPL) developed the precursor to the DSN system and program...

Citation Context

...global communication network to supportsinterplanetary space missions as well as to perform astronomical observations of the solar system andsbeyond.sThe history of the DSN is well summarized in Ref. =-=[44,45]-=- and the origins of the DSN programsbegan around 1958.sBefore the DSN was officially sanctioned, the U.S. Army and Jet PropulsionsLaboratory (JPL) developed the precursor to the DSN system and program...

Citation Context

...y. All rights reserved.sor water while under full pilot control.sTherefore, these incidents are often the result of crew error,sinstrument error, air traffic control error, or poor weather conditions =-=[42,43,50]-=-.sCFIT incidents weresthe leading cause of aviation accidents and fatalities in the world at least through the late 1990’s, and thesdecrease in CFIT incidents since then is one of the most significant...

Citation Context

... PASS and included metricsssuch as global temperature change, cost, fuel burn, and NOx emissions.sWaitz led MIT’s most focused research on evaluating the tradeoffs associated with aircraft operations =-=[74]-=-.sThis study specifically used a low-speed aerodynamic model and trajectory simulation to quantify thestradeoffs associated with cruise operations including that amongst performance (altitude and clim...

Citation Context

...ated tradeoff dimensions.sIn 2010, Campbell performed studies withsthe objective of reducing the environmental impact of aircraft operations by changing their respective inflight paths (trajectories) =-=[75]-=-.sThe tradeoffs specifically considered were contrail formation, fuel cost,sperformance (trajectory profile and flight time), and disturbance avoidance as manifested by avoiding staticsand dynamic, ha...

Citation Context

... literature investigating environmental andsperformance tradeoffs for aircraft cruise operations for the Climate Compatible Air Transport (CATS)sSystem and Aviation Integrated Modelling (AIM) Project =-=[76,77]-=-.sThe work on the CATS System wasspublished in 2009 and it specifically analyzed aircraft cruise operations by considering the tradeoffssamongst: engine technology (capability), contrail formation, pe...

Citation Context

...e that the λ’s are all negative since they correspond to systemsoutputs that are costs.sIn Table 6-1, current values were used for the hourly operating cost of an A320-200 and the price of Jet-Asfuel =-=[78,79]-=-; note that the operating cost does not include the cost of fuel since this is a separate systemsoutput.sThe social costs of CO2 and NOx emissions are based on recommendations from an InteragencysWork...

Citation Context

...e that the λ’s are all negative since they correspond to systemsoutputs that are costs.sIn Table 6-1, current values were used for the hourly operating cost of an A320-200 and the price of Jet-Asfuel =-=[78,79]-=-; note that the operating cost does not include the cost of fuel since this is a separate systemsoutput.sThe social costs of CO2 and NOx emissions are based on recommendations from an InteragencysWork...

Citation Context

...tem outputs corresponding to a given simplified cruise trajectory are computed with a modelscomprised of Piano-5, a professional aircraft modeling tool and a custom aircraft performance postprocessor =-=[82]-=-.sFor a given cruise trajectory, flight time, fuel burn, and emissions are computed withsPiano-5.sThen, based on the cruise flight trajectory and external factors, the length of contrails producedsand...

Citation Context

...ese regions are formulatedsusing the Schmidt-Appleman criterion for contrailss[83].sIn the cruise environment, the weather data atsaltitude are populated by the Rapid Update Cycles(RUC) weather model =-=[84]-=-.sAnd, lastly, thesturbulence severity regions in Figure 6-4 aresapproximated from Graphical Turbulence Guidances(GTG2) data provided by the National Oceanic andsAtmospheric Administration’s (NOAA) Av...

Citation Context

...ion and Performance (RNAV/RNP) procedures, which are enabledsby GPS technology; these procedures are briefly discussed hereafter and a more extensive discussion ofsRNAV and RNP can be found in Muller =-=[88]-=-.sRNAV is specifically responsible for creating point-to-pointsspeed and direction directives largely independent of Navigation Aid Systems (NAVAIDs) located on thesground, whereas RNP specifies the r...

Citation Context

...ories with a multiobjective function comprised of flight time, number of awakenings (noise proxy), and fuel burn (emissions98s© 2012 Massachusetts Institute of Technology. All rights reserved.sproxy) =-=[95]-=-.sLastly, the Enhanced Trajectory Prediction Model (ETPM), which is four-dimensional aircraftstrajectory optimization model, was developed to optimize aircraft cruise phases in terms of altitude while...

Citation Context

...tion) is exposed to 60+ dB of aircraft noise per day.sFor thestime-above metric, the 60 dB(A) threshold was chosen because this is the minimum noise level likely tosinterfere with normal conversation =-=[107]-=-.sFlight Times(hrs)sFuel Burns(gals)sCO2s(kg)sNOxs(kg)sContrailss(nm)sTurbulences(hrs)sAirlinesPassengerssGlobalsCommunitysIndirect Benefit Direct Cost Benefit CostsFigure 7-3.sStakeholder and System ...

Citation Context

... λNoise for the community is based on recommendationssfrom the Aviation Environmental Portfolio Management (APMT) Tool regarding a person’s willingness tospay to avoid being exposed to aircraft noise =-=[109]-=-.sAPMT estimates λNoise to be roughly 0.06 $ per personhour of exposure to 60+ dB of aircraft noise; therefore, the community stakeholder only incurs the cost ofsnoise when a population is exposed to ...