The Italian Space Agency (ASI) recently decided to put together a satellite subsystem development phase Cost and Time estimating Parametric Model. The model is based on the Complexity Index theory developed by David B...
详细信息
ISBN:
(纸本)1563479079
The Italian Space Agency (ASI) recently decided to put together a satellite subsystem development phase Cost and Time estimating Parametric Model. The model is based on the Complexity Index theory developed by David Bearden applied at subsystem level to a number of ASI satellite programs. For each subsystem technical data as well as cost and schedule data related to the development phases (phase C/D) was collected. The complexity index for each subsystem was then obtained and IRLS (Iteratively Re-weighted Least Squares) regressions were applied to obtain functions that linked the complexity to cost and separately, to development time. The obtained functions were packaged in Excel using visual basic. When using the model to obtain an estimate, the continuous input technical attributes can be specified as distributions in order to generate complexity index distributions and therefore, cost and development time estimate distributions.
An impact of dynamic channel allocation, opportunistic scheduling and smart antennas on inter-cell interference, and consequently on system performance is studied in this paper. It is shown that from the receiver poin...
详细信息
ISBN:
(纸本)1424416620
An impact of dynamic channel allocation, opportunistic scheduling and smart antennas on inter-cell interference, and consequently on system performance is studied in this paper. It is shown that from the receiver point of view the most effective inter-cell interference reduction method is the opportunistic scheduling, followed by smart antennas, and dynamic channel allocation. Furthermore, interesting trade-offs that can be made by combining these techniques are observed as well.
In this paper we design and implement a 2D coupled mobility snake/caterpillar vehicle for terrains with variable friction. A control hierarchy made of fuzzy logic controllers equipped with fuzzy actor critic learning ...
详细信息
The radio communication systems for an unmanned scaled supersonic experimental airplane NEXST-1 consist of three kinds of system of telemetry, command and radar-transponder including ground and onboard equipments. Thi...
详细信息
ISBN:
(纸本)1563478935
The radio communication systems for an unmanned scaled supersonic experimental airplane NEXST-1 consist of three kinds of system of telemetry, command and radar-transponder including ground and onboard equipments. This paper discusses the results of the system design and antenna pattern test during the design and development phase. And then the paper verifies the results of RF link design by comparing with the analyzed flight test data of RSSI and SS obtained for the 15 minuets and 22 seconds, as well as the positioning comparison between IMU and Radars. The analysis results of the RF link include the exhaust plumes effect for the verification in the flight.
We present an approach to fault management based on an architecture for distributed and collaborative network management as developed in the CELTIC project Madeira. It uses peer-to-peer communication facilities and a ...
详细信息
This paper documents the activity of a workshop on defining a research agenda for systems of systems (SoS) Architecting, which was held at USC in October 2006. After two days of invited talks on critical success facto...
详细信息
Bioremediation represents one of the most cost-effective technologies for treatment of petroleum hydrocarbons in contaminated surface soils. A major concern for regulatory agencies when evaluating bioremediation is ho...
详细信息
Bioremediation represents one of the most cost-effective technologies for treatment of petroleum hydrocarbons in contaminated surface soils. A major concern for regulatory agencies when evaluating bioremediation is how to determine acceptable levels for residual organics in soil. Although guidelines have been developed for some organics in soil, limited information is available to define acceptable levels of the metabolites of biological degradation. The products of oxidative degradation are likely to be more water soluble and may also be more toxic. The purpose of the current study was to monitor changes in compound concentration and genotoxicity in soils undergoing bioremediation. The site selected for this study was a former wood-preserving site in the northwestern United States. Soil samples were collected over a 4-year period from two 6075-m2 land treatment units. Conditions for biodegradation were enhanced by the addition of water and nutrients, as well as by frequent tilling to add oxygen. Due to the location of the facility, the temperature was conducive to a more rapid rate of biodegradation for approximately 6 months per year. Soil samples were collected using a grid system and solvent extracted. Polycyclic aromatic hydrocarbons were quantified in soil extracts using gas chromatography-mass spectrometry (GC/MS), and genotoxicity measured using the Salmonella/microsome assay. After 2 years of treatment, concentrations of total and carcinogenic polycyclic aromatic hydrocarbons (PAHs) were reduced to approximately 10% the concentration in the untreated soil. However, the mean weighted activity of the untreated soil was 293 net revertants per g soil, whereas the extracts of soil collected after 2 years induced a mean weighted activity of 325 net revertants per g soil. Thus, although biodegradation clearly reduced the concentration of total and carcinogenic PAHs in the surface soils, the results from the genotoxicity bioassay indicate that there was a lag in th
We show the feasibility of more cost-effective long-haul transmission using Fiber Bragg Gratings (FBG) for in-line dispersion compensation. 32x10.7-Gbit/s NRZ modulated channels are transmitted over 40x95 km of SSMF u...
详细信息
Sediment transport in a gravel-bed mountain stream, the Upper Spanish Creek, California, was simulated with a depth-averaged, two-dimensional hydrodynamic and sediment transport model. The hydrodynamic model is based ...
详细信息
暂无评论