Optimization of System Performance for DVC Applications with Energy Constraints over Ad Hoc Networks

Distributed video coding (DVC) is an emerging video coding paradigm designed to allow low-complexity compression by resource-constrained video sensor nodes in wireless video sensor networks (WVSN). Several DVC architectures have been proposed in literature but there are hardly any security mechanisms designed to validate the integrity and authenticity of the decoded video. In this paper, we propose a novel, low-complexity, blind, and imperceptible video watermarking scheme based on DVC for WVSNs. The watermark information is embedded into key frames under selected GOP (Group of Pictures) configurations. Considering the information-intensive yet resource-constrained WVSN environment, the proposed scheme aims to limit the impact of watermark embedding complexity by hiding the secret information using non-zero quantized AC coefficients. We implemented the proposed watermarking scheme for a DVC based codec and evaluated its processing complexity (encoding/decoding). We also evaluated the average normalized correlation between the embedded and extracted watermarks for different video sequences by varying the redundancy in embedding.

This paper studies a multi-tier cache-aided relaying network, where the destination <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$D$ </tex-math></inline-formula> is randomly located in the network and it requests files from the source <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S$ </tex-math></inline-formula> through the help of cache-aided base station (BS) and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N$ </tex-math></inline-formula> relays. In this system, the multi-tier architecture imposes a significant impact on the system collaborative caching and file delivery, which brings a big challenge to the system performance evaluation and optimization. To address this problem, we first evaluate the system performance by deriving analytical outage probability expression, through fully taking into account the random location of the destination and different file delivery modes related to the file caching status. We then perform the asymptotic analysis on the system outage probability when the signal-to-noise ratio (SNR) is high, to enclose some important and meaningful insights on the network. We further optimize the caching strategies among the relays and BS, to improve the network outage probability. Simulations are performed to show the effectiveness of the derived analytical and asymptotic outage probability for the proposed caching strategy. In particular, the proposed caching is superior to the conventional caching strategies such as the most popular content (MPC) and equal probability caching (EPC) strategies.

This software is aimed at providing engineering design personnel who are engaged in marine gas turbine power system design and performance optimization with a software platform for concentrated design and management. First, the mathematical model of the sub-shaft gas turbine was established using volume inertia and rotor inertia method. And then the relative non-linear simulation module base of all components was built based on MATLAB/Simulink. Second, in order to develop this extensible simulation software for the study on the marine gas turbine overall performance, a human-computer interface was cultivated too based on MATLAB/GUI. This software provides the functions of analyzing dynamic performance of the marine gas turbine power system in both on-design and off-design operating conditions. It offers engineering design personnel an extensible and useful GUI platform in gas turbine system design and performance optimization.

Power control algorithms for mobile ad hoc networks

Next generation communication networks will comprise third-generation (3G) cellular and multi-hop ad hoc networks. The paper has evaluated the end-to-end performance of TCP over a multi-hop cellular network that comprises the enhanced universal mobile telecommunications system (UMTS), namely, HSDPA and the IEEE 802.11 ad hoc networks for bulk data transfers under different HSDPA radio channel quality as well as number of hops. The throughput simulation results show that bottleneck of the multi-hop cellular network shifted between the UMTS/HSDPA network and the ad hoc network based on the different channel quality and number of hops. Ad hoc network can increase the service range of cellular network, and also improve the performance for the end-user who experiences bad channel conditions. Moreover, the relation between HSDPA radio channel usage and end-to-end user experience under different network configurations and channel conditions is also revealed. Our result can be used to select optimal routes and system performance optimization.

Accurate modeling of direct-detection lightwave systems is required for system performance assessment and optimization, especially in the presence of impairments. System optimization, though, is generally numerically intensive and notably so when trying to accommodate the full range of impairments that are representative of practical systems.

It is important to design and operate energy conversion systems such as gas turbine cogeneration ones optimally from the thermoeconomic viewpoint. However, an energy conversion system has a complex network structure, and it takes much time to create its model for the thermoeconomic analysis and optimization. In this paper, a systems approach is presented for the performance analysis and optimization of mechanical systems with network structures, and it is applied to the thermoeconomic analysis and optimization of a gas turbine cogeneration unit. The system modeling for the performance analysis is conducted by a building block approach. Static and dynamic problems for the performance analysis are formulated as sets of nonlinear algebraic and differential algebraic equations, and are solved by the Newton-Raphson method and a hierarchical combination of the Runge-Kutta and Newton-Raphson methods, respectively. The performance optimization is conducted to determine design and operation conditions which optimize performance criteria. This problem is formulated as a nonlinear programming one and is solved by a global optimization method. In the application, the cycle analysis is conducted to determine mass flow rates, pressures, and temperatures, which is followed by the exergy and cost analyses to determine exergy flow rates and efficiencies, and capital costs, respectively. In addition, design and operation conditions are determined to maximize the exergy efficiency or minimize the annual total cost based on the results of the cycle, exergy, and cost analyses. Through a numerical study, it turns out that the proposed systems approach enables one to conduct the thermoeconomic analysis and optimization efficiently.

Statistical engineering is the study of how to best utilize and integrate statistical methods with other engineering disciplines and information technology to solve high-level, complex, multidisciplinary problems. Engineering disciplines apply the principles or “building blocks” of the sciences to design something new or to improve something already in existence, frequently a machine, tool, or structure (Hoerl and Snee 2010b). Statistical engineering involves the application of the principles of probability and statistics, in conjunction with the work of other engineers and scientists, to quantify and control variability, uncertainty, and risk in order to improve a process, product, or service. The design for variation (DFV) process developed at Pratt & Whitney and described in this article is shown to possess all attributes of a statistical engineering application. Design for variation, a strategic initiative at Pratt & Whitney, represents a large-scale improvement of engineering design and analysis processes in order to quantify and reduce variability, uncertainty, and risk, requiring the efforts of engineers, statisticians, and information technology specialists. This article also presents examples of the DFV process as applied to turbine airfoil cooling, high cycle fatigue, hollow fan blade producibility, and optimization of thermal management systems and overall system performance. The new ‘DFV-enabled’ processes help engineers to actively manage variability, uncertainty, and risk directly via design, materials, and process changes.

The optimal use of geothermal energy necessitates the performance evaluation and economic analysis of the geothermal heating systems. This work presented a field study of the long-term operating performance of a geothermal heating system in Xixian New Area, China. Nine deep coaxial ground heat exchangers (GHEs) with depths of 2,500 m were adopted for space heating to the residential buildings, with a total heating area and heating load of 136,097.71 m2 and 6,082 kW, respectively. The system’s 30-year running performance at various volumetric flow rates and operating modes was simulated. Through response surface analysis and multi-objective optimization, the levelized cost of energy (LCOE) and payback period were obtained based on the thermal performance analysis. It is concluded that the operating parameters have a significant impact on the system economy. When the daily operating time reduces from 24 hours to 8 hours, the payback period will be lowered from more than 25 years to approximately 11 years. When the volumetric flow rate is 35 m3·h-1, the examined system achieves the lowest LCOE. The minimum values of LCOE are 13.2 $/GJ, 11.6 $/GJ, 9.4 $/GJ, 7.8 $/GJ and 5.6 $/GJ when the system operates 24 hours (continuous operation), 20 hours, 16 hours, 12 hours and 8 hours a day, respectively. With the optimal flow rate, the average heat exchange rate of the single GHE increases from 295 kW to 519 kW after 30 years of operation when the daily operating time is reduced from 20 hours to 8 hours. The proposed method and findings can be used to guide the high-efficiency operation, which is conducive to reducing operating costs of geothermal heating systems.

Multi-objective design optimization of battery thermal management system for electric vehicles

This paper analyzed self-similarity of Ad-hoc network traffic, and how the network performance was influenced by the self-similarity. Based on Fractional Brownian Motion model, paper proposed a self-similar traffic sequence generation method of RMD algorithm. RMD algorithm is one of the self-similar statistic models. Furthermore, simulation and modeling for Ad-hoc tactic network was implemented based on this kind of traffic model. According to the each performance indicator of curve contrast chart generated by simulating experiment, conclusion is made as follow: self-similarity has great influence to Ad-hoc network indicator and has great contrast to traditional flow models’ short-range dependency character. The research result of this thesis has significant meaning for precise modeling of Ad-hoc network flow, resource optimization and improvement of network performance.

Performance analysis and optimization of organic Rankine cycle (ORC) for waste heat recovery

Data-driven optimization methods play a major role in industrial system performance optimization. As the requirements for performance optimization efficiency become more and more stringent, the efficiency of data-driven methods becomes the key to their application. The efficiency of the data-driven methods mainly depends on their algorithm parameter settings. However, the current parameters settings scheme optimization process is usually conducted in trial-and-error mode, which depends on the experience of engineers or researchers, and is cumbersome and time-consuming. To address this problem, this paper proposes a closed-loop datadriven optimization method, which can guide the improvement of the next optimization process through the morphological characteristics of the current optimization process. In this method, the Visual Geometry Group(VGG) neural network is used to obtain the morphological characteristics of the current optimization process to guide the data-driven algorithm based on Simultaneous Perturbation Stochastic Approximation (SPSA) to improve the current optimization process, realize the auxiliary optimization of control parameters, and show the role of using multidimensional data to assist the traditional control method to achieve rapid convergence and achieve high efficiency and economy. Simulation experiments were conducted on the performance optimization of the steam generator level control system. The simulation results showed that this method is feasible and could be assisted in optimizing the control parameters of the data-driven optimization methods.

Distributed Video Coding (DVC) is an emerging video coding paradigm for the systems that require encoders having low complexity that are supported by decoders having high complexity as would be required for, say, real-time video capture and streaming from one mobile phone to display on another. Under the assumption of an error-free transmission channel, the coding efficiency of current DVC systems is still below that of the latest conventional video codecs, such as H.264/AVC. To increase coding efficiency we propose in this paper that either every second Key frame or every Wyner-Ziv frame is downsampled by a factor of two in both dimensions prior to encoding and subsequent transmission. However, this would necessitate upsampling coupled with interpolation at the decoder. Simple interpolation (e.g., bilinear or FIR filter) would not suffice since high-frequency (HF) spatial image content would be missing. Instead, we propose the incorporation of a super-resolution (SR) technique that is based upon using example High Resolution images with content that are specific to the Low Resolution scene that needs its HF content to be recovered. The example-based scene-specific SR technique will add computational complexity to the decoder side of the DVC system, which is allowable within the DVC framework. Rate-distortion curves will show that this novel combination of SR with DVC improves the system performance by up to several decibels as measured by the PSNR, and can actually exceed the performance of an H.264/AVC codec, using GOP=IP, for some video sequences.

Utilizing descriptive research, this study assessed the system efficiency, challenges, and user satisfaction of the Online Permits Application System of the Environmental Management Bureau (EMB) MIMAROPA under the Department of Environment and Natural Resources (DENR) in San Jose, Occidental Mindoro. The randomly chosen 180 business owners, pollution control officers, environmental consultants, private citizens, and local government personnel who applied for permits online and had used the system served as the respondents. Data was collected using a structured survey questionnaire. The respondents confirmed the very high efficiency (mean=4.56) and very high user satisfaction (mean=4.58) of the online application system. They likewise reported the slightly serious challenges (mean=1.67) encountered in its use. Correlation analysis revealed the negative relationship between system efficiency and challenges (r=-0.443), and between challenges and user satisfaction (r=-0.282) which emphasized that the optimization of system performance would help reduce barriers and enhance user contentment. In contrast, the positive correlation (r = 0.442) between satisfaction and efficiency indicates that efficient processes, accessibility, and timely service delivery are associated with user appreciation of the online permit application system. Although rated highly efficient, it is necessary to provide continuous system maintenance, performance monitoring, and user feedback mechanisms. To sustain long-term efficiency, reliability, and successful delivery of e-government services, training and seminars are needed for the system administrators. Strengthening support services, digital assistance, system guidance, enhanced user-centered system features, regular updating of security measures, and an integrated system improvement framework are likewise recommended.