System Performance Criteria Research Articles

Transmit-Receive Antenna Pair Selection in Full Duplex Systems

In this letter, a novel transmit-receive antenna pair selection (TRAPS) scheme is proposed for bidirectional full-duplex (FD) communications between two nodes, where each node is equipped with two antennas, used for either transmission or reception. Specifically, one transmit and receive antenna combination is selected based on two system performance criteria: 1) maximum sum-rate (Max-SR), and 2) minimum symbol-error-rate (Min-SER). For the Max-SR approach, we obtain a sum-rate upper bound. And for the Min-SER, a SER lower bound is derived, by introducing a simple near-optimal Min-Max criterion. Finally, we compare the proposed TRAPS approaches with the traditional FD communication system in terms of average sum-rate and SER, respectively. Simulation results verify our analysis, and show a significant performance improvement.

철도차량 미분무수 소화설비 성능 평가

The test system for the performance of the water-mist extinguishing system in the railway vehicle is equipped and the details of the system are introduced. The three scenarios using different fire sources and performance criteria for the water-mist systems on railway vehicles are also introduced. Three different type of the nozzle at same operating pressure are evaluated. Amount of water-mist distribution is measured by many baskets on the bottom of the test room. Temperature on the ceil and the tree of the test room is measured during the tests that are used for the judgement of the performance on the water-mist extinguishing system.

System of systems analytic hierarchy and stochastic optimisation design

A formulated methodology of developing the system of systems analytical hierarchy and optimisation flow order is presented. The design problem is modelled as a multi-level hierarchical optimisation problem. The multi-levels such as, super system level, system level and subsystem level are defined. Based on the idea of system of systems, each system performance criteria can be decomposed into several subsystems according to their individual functions. At the super system level, performance objective function is considered by minimising the variances between specified expected values of performance functions and their target values and uncertainty effects caused by global variables. The different levels are linked by the global variables. At the same level, all the subsystems are connected by the linking variables. The local variables only give contributions to each according local subsystem. A specified way to decide cascading flow order for the multi-level system optimisation decision-making problem introduced to improve convergence speed, by considering the sensitivity analysis of linking variables for each element. The formulated method is applied to the selected system of systems examples, such as, the sensor network example. The optimised results based on methods such as genetic algorithm (GA) are provided.

PID Controller Design for MIMO Processes Using Improved Particle Swarm Optimization

This paper aims at the PID control system design for multivariable input and multivariable output (MIMO) processes. An improved version of a particle swarm optimization (PSO) algorithm is utilized to design PID control gains in MIMO control systems. In addition to the individual best and the global best particles, the velocity updating formula of the developed algorithm includes a new factor, the best particle of each sub-population, to enhance the search capacity. Based on the improved particle swarm optimization (IPSO), a complete design strategy is proposed for MIMO PID control systems. All control gains will be evolved to the optimal values by minimizing the system performance criterion. To show the efficiency of the proposed design method, a multivariable chemical process system with two inputs and two outputs is illustrated. Some experiment results, including different algorithm parameter settings and comparisons with other methods, are given. Numerical simulations indicate that the proposed method is superior to other optimal methods.

농업용 둑높임저수지의 다중 용수공급을 위한 이수운영기준곡선 개발

ABSTRACT This study developed an operating rule curve (ORC) for multipurpose water supply (irrigation and environmental water) in height ened agricultural reservoir. Among the 20 reservoirs in improvement pr oject of agricultural reservoir dam heightening, the 4 represe ntative reservoirs (Ungyang, Gungchon, Yongam and Unam) were selected for the study according to the analysis of statistical characteri stics. Available environmental water supply amounts during irrigation and non-irrigation periods, which is the range from release rest ricted water level to high water level were estimated by water balance analysis using reservoir operation model. Reliability, resiliency and vulnerability criteria for water system performance were used to assess the multiple water supply capacity. The ORC was present ed as the percentile rank for the daily reservoir water level from the results of reservoir operation using the past couple of decade s weather data. The water levels for each percentile were divi ded into 3 buffer sections representing drought (5 ～25%), normal (25 ～75%), and flood (75～95%) year to operate the heightened agricultural reservoir with ORC.

Optimal production of renewable hydrogen based on an efficient energy management strategy

This work presents the development of a flexible energy management strategy (EMS) for a renewable hydrogen production unit through water electrolysis with solar power. The electricity flow of the unit is controlled by a smart microgrid and the overall unattended operation is achieved by a supervisory control system. The proposed approach formalizes the knowledge regarding the system operation using a finite-state machine (FSM) which is subsequently combined with a propositional-based logic to describe the transitions among various process states. The operating rules for the integrated system are derived by taking into account both the operating constraints and the interaction effects among the individual subsystems in a systematic way. Optimal control system parameter values are obtained so that a system performance criterion incorporating efficient and economic operation is satisfied. The resulted EMS has been deployed to the industrial automation system that monitors and controls a small-scale experimental solar hydrogen production unit. The overall performance of the proposed EMS in the experimental unit has been evaluated over short-term and long-term operating periods resulting in smooth and efficient hydrogen production.

A Concurrent Modelling to Generate Alternatives Approach Using the Firefly Algorithm

Real world” decision-making applications generally contain multifaceted performance requirements riddled with incongruent performance specifications. There are invariably unmodelled elements, not apparent during model construction, which can greatly impact the acceptability of the model’s solutions. Consequently, it is preferable to generate numerous alternatives that provide dissimilar approaches to the problem. These alternatives should possess near-optimal objective measures with respect to all known objective(s), but be maximally different from each other in terms of their decision variables. This maximally different solution creation approach is referred to as modelling-to-generate-alternatives (MGA). This study demonstrates how the Firefly Algorithm can concurrently create multiple solution alternatives that both satisfy required system performance criteria and yet are maximally different in their decision spaces. This new approach is computationally efficient, since it permits the concurrent generation of multiple, good solution alternatives in a single computational run rather than the multiple implementations required in previous MGA procedures.

Generating Alternatives Using Simulation-Optimization Combined with Niching Operators to Address Unmodelled Objectives in a Waste Management Facility Expansion Planning Case

Public sector decision-making typically involves complex problems that are riddled with incompatible performance objectives and possess competing design requirements which are very difficult – if not impossible – to quantify and capture when supporting decision models need to be constructed. There are invariably unmodelled design issues, not apparent at the time of model creation, which can greatly impact the acceptability of the solutions proposed by the model. Consequently, it is generally preferable to create several quantifiably good alternatives that provide multiple, disparate perspectives and very different approaches to the particular problem. These alternatives should possess near-optimal objective measures with respect to the known modelled objective(s), but be fundamentally different from each other in terms of the system structures characterized by their decision variables. By generating a set of very different solutions, it is hoped that some of the dissimilar alternatives can provide very different perspectives that may serve to satisfy the unmodelled objectives. This study shows how simulation-optimization (SO) modelling can be combined with niching operators to efficiently generate multiple policy alternatives that satisfy required system performance criteria in stochastically uncertain environments and yet are maximally different in the decision space. This new stochastic approach is very computationally efficient, since it permits the simultaneous generation of good solution alternatives in a single computational run of the SO algorithm. The efficacy and efficiency of this modelling-to-generate-alternatives (MGA) method is specifically demonstrated on a municipal solid waste management facility expansion case.

A study on appropriateness of performance criteria of smoke control system among the local fire safety standard for underground spaces

This study is intended to evaluate the characteristics of smoke spreading and the appropriateness of evacuation time extended by operation of smoke control system during fire within the underground space of the building structured in compliance with the smoke control system performance criteria from the local fire safety standard, which has been currently applied to the buildings in Korea. As a preced- ing review, the heat release of the combustibles was identified and based on outcome thereof; the type and specification of the combustibles existing at the possible fire location were examined, estimating the heat releases. In a bid to validate the estimated values, modeling a single underground shopping mall was carried out, and the combustibles examined during the preceding review was placed inside the building for a real scale fire test, the result of which was then reviewed and compared with a numerical analysis result. Using the heat release per unit weight of the combustibles, a numerical analysis both in case of smoke control system in operation and the system not in operation was carried out at several different shopping malls. From the viewpoint of securing the evacuation time, the results were com- pared in an attempt to assess the appropriateness of the fire safety criteria. Keywords Evacuation, smoke control, underground market Language: en

Robust Decision Making and Info-Gap Decision Theory for water resource system planning

Stationarity assumptions of linked human–water systems are frequently invalid given the difficult-to-predict changes affecting such systems. In this case water planning occurs under conditions of deep or severe uncertainty, where the statistical distributions of future conditions and events are poorly known. In such situations predictive system simulation models are typically run under different scenarios to evaluate the performance of future plans under different conditions. Given that there are many possible plans and many possible futures, which simulations will lead to the best designs? Robust Decision Making (RDM) and Info-Gap Decision Theory (IGDT) provide a structured approach to planning complex systems under such uncertainty. Both RDM and IGDT make repeated use of trusted simulation models to evaluate different plans under different future conditions. Both methods seek to identify robust rather than optimal decisions, where a robust decision works satisfactorily over a broad range of possible futures. IGDT efficiently charts system performance with robustness and opportuneness plots summarising system performance for different plans under the most dire and favourable sets of future conditions. RDM samples a wider range of dire, benign and opportune futures and offers a holistic assessment of the performance of different options. RDM also identifies through ‘scenario discovery’ which combinations of uncertain future stresses lead to system vulnerabilities. In our study we apply both frameworks to a water resource system planning problem: London’s water supply system expansion in the Thames basin, UK. The methods help identify which out of 20 proposed water supply infrastructure portfolios is the most robust given severely uncertain future hydrological inflows, water demands and energy prices. Multiple criteria of system performance are considered: service reliability, storage susceptibility, capital and operating cost, energy use and environmental flows. Initially the two decision frameworks lead to different recommendations. We show the methods are complementary and can be beneficially used together to better understand results and reveal how the particulars of each method can skew results towards particular future plans.

Selecting Portfolios of Water Supply and Demand Management Strategies Under Uncertainty—Contrasting Economic Optimisation and ‘Robust Decision Making’ Approaches

Planning appropriate portfolios of new water supplies and demand management measures requires considering a wide array of options and their interactions over a largely unknown future. Various modelling-assisted approaches are available to help this planning process. This paper applies two such frameworks to the UK’s Thames water resource system and compares their methods and outputs: how they consider uncertainty, how they represent supply and demand management options, and what plans each recommends. The first method is the current England and Wales industry standard: annual least-cost capacity expansion optimisation over a 25 to 30 year time horizon considering capital, operating (fixed and variable), social and environmental costs. The second approach uses stochastic simulation and regret analysis to select a preferred alternative, then statistical cluster analysis to identify causes of system failure enabling further plan improvement. When applied iteratively with system planners this second approach is referred to as Robust Decision Making (RDM). The economic optimisation approach considers all plausible combinations of supply and conservation schemes and recommends the least-cost schedule of their implementation. Our RDM application considers a smaller number of options but makes a more detailed assessment of the effect of uncertainty (supply, demand and energy price uncertainty were considered) on multiple criteria of system performance. The simulation-based approach also enables more realistic interaction amongst supply and demand management schemes. Both approaches recommended different plans which we explain by discussing the benefits and limitations of each. Joint application is recommended to produce least-cost plans that are robust considering multiple criteria of performance across a wide range of futures.

Multiple-domain design scorecards: a method for architecture generation and evaluation through interface characterisation

High-tech mechatronic system design, such as that required for tools for oil-well drilling and exploitation, requires that engineers from multiple domains concur on architectural solutions due to a large number of interdependent system performance criteria and design parameters that are shared across architecture interfaces. Supporting designers in envisioning probable challenges in architectures early in design is of utmost importance to ensure project quality while minimising costs and delays. In this paper, we present the multiple-domain design scorecard method to facilitate architecture generation and assessment through architecture interface characterisation as well as to support design process management. We propose to semantically enrich the design structure matrix, domain mapping matrix and quality function deployment representations to capture project data and expertise related to concept generation. In addition, we propose six types of design assessment cards that both support design space exploration and highlight design challenges of potential system architecture. The proposed approach is being implemented and tested in an industry context. A case study in the oil industry brings to the fore some of the advantages and challenges in the implementation process.

An Autopilot Based on a Local Control Network Design for an Unmanned Surface Vehicle

Over recent years, a number of marine autopilots designed using linear techniques have underperformed owing to their inability to cope with nonlinear vessel dynamics. To this end, a new design framework for the development of nonlinear autopilots is proposed. Local Control Networks (LCNs) can be used in the design of nonlinear control systems. In this paper, a LCN approach is taken in the design of a nonlinear autopilot for controlling the nonlinear yaw dynamics of an unmanned surface vehicle known as Springer. It is considered the approach is the first of its kind to be used in marine control systems design. Simulation results are presented and the performance of the nonlinear autopilot is compared with that of an existing Springer Linear Quadratic Gaussian (LQG) autopilot using standard system performance criteria. From the results it can be concluded the LCN autopilot out-performed that based on LQG techniques in terms of the selected criteria. Also it provided more energy saving control strategies and would thereby increase operational duration times for the vehicle during real-time missions.

Development of narrow band spectral-sliced wavelength division multiplexing (WDM) system and its performance in optical access networks

In this paper, we have proposed a narrow band spectral-sliced wavelength division multiplexing (WDM) system and investigated its performance for optical access networks application. In the proposed system, the low cost light emitting diodes (LEDs) are used as the broad band light source. The system performance investigation was carried out using non-return-to-zero (NRZ) and return-to-zero (RZ) modulation format by OptiSystem Software, Version 7.0. We used two network system models, the first one used RZ pulse generator and the second one used NRZ pulse generator, and both systems are tested without any amplifier. It was found that NRZ pulse generator signal performance is better than those of RZ pulse generator. The proposed system network simulation runs at different bit rates (BR), such as 622 Mb/s, 1 and 1.5 Gb/s, respectively. We ascertained from the network simulation results that the proposed system exhibits better performance at 622 Mb/s as compared to others bit rates. Furthermore, the overall system performances are characterized through bit-error-rate (BER) and BR including the received optical power at various BR. In this analysis, the BER performance has been considered as the main system performance criterion. It has been shown, that the proposed method with NRZ modulation technique provides improved transmission performance as compared to the return-to-zero modulation technique. Key words: Non-return-to-zero/Return-to-zero modulation format, spectral slicing, wavelength division multiplexing (WDM).

Development of a simulation model of biomass supply chain for biofuel production

Biofuel production from renewable biomass has experienced increased interest in order to reduce U.S. dependence on imported oil and reduce carbon emissions. Concerns regarding cost efficiency and environmental problems result in significant challenges that hinder the increased biofuel production from renewable biomass. This paper describes the development of a simulation model with an easy-to-use graphical user interface for the biofuel supply chain. The model considers key supply chain activities including biomass harvesting/processing, transportation, and storage. The model uses the delivered feedstock cost, energy consumption, and GHG emissions as system performance criteria. The utility of the supply chain simulation model is demonstrated by considering a biomass supply chain for a biofuel facility in the lower peninsula of Michigan. The results show that the model is a useful tool for supply chain management, including selection of the optimal biofuel facility location, logistics design, inventory management, and information exchange.

Evaluation of Operating Domains in Power Systems

This paper presents the results of a recent major industry-supported study with the aim to provide power system operators with more meaningful and effective means to quickly identify feasible operating boundaries as well as more flexibility to select alternate operating scenarios. In this regard, the paper outlines the main theoretical basis and computational framework for the development of innovative computerized schemes capable of identifying and processing various system integrity domains. The novel framework allows system operators to determine – in a fast and reliable manner – the most favorable operating scenarios which maintain system security, reliability and operating performance quality. For demonstration purposes, and without loss of generality, an emphasis is given to the dynamic system security problem where the Transient Energy Function (TEF) method is used to define quantitative measures of the level (degree) of system security for a given operating scenario. Nonetheless, the framework presented is applicable quite as well to other system performance functions and criteria that may be considered. A demonstrative application is presented for a 9-bus benchmark system, widely used in the literature. In addition, a practical application is also presented for the Saudi Electricity Company (SEC) power system where the operating security domain was evaluated in the operating parameter space spanned by two major interface flows in the system.

A Local Control Network Autopilot for an Unmanned Surface Vehicle

Although marine craft are renowned for their nonlinear dynamic behaviour, autopilot system designs are still being developed based on linear control methodologies. Thus to overcome any limitations in the performance capabilities of such systems, it is appropriate to consider designing nonlinear autopilots. This paper reports an investigation into a novel approach to marine control systems design based on local control network (LCN) techniques. The approach is used to design an autopilot for controlling the nonlinear yaw dynamics of an unmanned surface vehicle and is benchmarked against another based on a standard proportional-integral-derivative controller. Simulation results are presented and the performances of the autopilots are compared using standard system performance criteria. From the results it can be observed that the LCN is more efficient compared to the PID controller. Also it out performs its PID counterpart in terms of the selected criteria. Copyright © 2012 IFAC

Performance Evaluation and Labeling Comprehension of a New Blood Glucose Monitoring System with Integrated Information Management

This study evaluated performance and product labeling of CONTOUR® USB, a new blood glucose monitoring system (BGMS) with integrated diabetes management software and a universal serial bus (USB) port, in the hands of untrained lay users and health care professionals (HCPs). Subjects and HCPs tested subject's finger stick capillary blood in parallel using CONTOUR USB meters; deep finger stick blood was tested on a Yellow Springs Instruments (YSI) glucose analyzer for reference. Duplicate results by both subjects and HCPs were obtained to assess system precision. System accuracy was assessed according to International Organization for Standardization (ISO) 15197:2003 guidelines [within ±15 mg/dl of mean YSI results (samples <75 mg/dl) and ±20% (samples ≥75 mg/dl)]. Clinical accuracy was determined by Parkes error grid analysis. Subject labeling comprehension was assessed by HCP ratings of subject proficiency. Key system features and ease-of-use were evaluated by subject questionnaires. All subjects who completed the study (N = 74) successfully performed blood glucose measurements, connected the meter to a laptop computer, and used key features of the system. The system was accurate; 98.6% (146/148) of subject results and 96.6% (143/148) of HCP results exceeded ISO 15197:2003 criteria. All subject and HCP results were clinically accurate (97.3%; zone A) or associated with benign errors (2.7%; zone B). The majority of subjects rated features of the BGMS as "very good" or "excellent." CONTOUR USB exceeded ISO 15197:2003 system performance criteria in the hands of untrained lay users. Subjects understood the product labeling, found the system easy to use, and successfully performed blood glucose testing.

Gain and offset calibration reduces variation in exposure‐dependent SNR among systems with identical digital flat‐panel detectors

The conditions under which vendor performance criteria for digital radiography systems are obtained do not adequately simulate the conditions of actual clinical imaging with respect to radiographic technique factors, scatter production, and scatter control. Therefore, the relationship between performance under ideal conditions and performance in clinical practice remains unclear. Using data from a large complement of systems in clinical use, the authors sought to develop a method to establish expected performance criteria for digital flat-panel radiography systems with respect to signal-to-noise ratio (SNR) versus detector exposure under clinical conditions for thoracic imaging. The authors made radiographic exposures of a patient-equivalent chest phantom at 125 kVp and 180 cm source-to-image distance. The mAs value was modified to produce exposures above and below the mAs delivered by automatic exposure control. Exposures measured free-in-air were corrected to the imaging plane by the inverse square law, by the attenuation factor of the phantom, and by the Bucky factor of the grid for the phantom, geometry, and kilovolt peak. SNR was evaluated as the ratio of the mean to the standard deviation (SD) of a region of interest automatically selected in the center of each unprocessed image. Data were acquired from 18 systems, 14 of which were tested both before and after gain and offset calibration. SNR as a function of detector exposure was interpolated using a double logarithmic function to stratify the data into groups of 0.2, 0.5, 1.0, 2.0, and 5.0 mR exposure (1.8, 4.5, 9.0, 18, and 45 microGy air KERMA) to the detector. The mean SNR at each exposure interval after calibration exhibited linear dependence on the mean SNR before calibration (r2=0.9999). The dependence was greater than unity (m = 1.101 +/- 0.006), and the difference from unity was statistically significant (p <0.005). The SD of mean SNR after calibration also exhibited linear dependence on the SD of the mean SNR before calibration (r2 = 0.9997). This dependence was less than unity (m = 0.822 +/- 0.008), and the difference from unity was also statistically significant (p < 0.005). Systems were separated into two groups: systems with a precalibration SNR higher than the median SNR (N = 7), and those with a precalibration SNR lower than the median SNR (N= 7). Posthoc analysis was performed to correct for expanded false positive results. After calibration, the authors noted differences in mean SNR within both high and low groups, but these differences were not statistically significant at the 0.05 level. SNR data from four additional systems and one system from those previously tested after replacement of its detector were compared to the 95% confidence intervals (CI) calculated from the postcalibration SNR data. The comparison indicated that four of these five systems were consistent with the CI derived from the previously tested 14 systems after calibration. Two systems from the paired group that remained outside the CI were studied further. One system was remedied with a grid replacement. The nonconformant behavior of the other system was corrected by replacing the image receptor. Exposure-dependent SNR measurements under conditions simulating thoracic imaging allowed us to develop criteria for digital flat-panel imaging systems from a single manufacturer. These measurements were useful in identifying systems with discrepant performance, including one with a defective grid, one with a defective detector, and one that had not been calibrated for gain and offset. The authors also found that the gain and offset calibration reduces variation in exposure-dependent SNR performance among the systems.

A new algorithm and multi-response Taguchi method to solve line balancing problem in an automotive industry

One of the most important issues in an assembly line balancing problem is to control a flow of production and manufacturing to provide continuous flow to balance the production line. For this purpose, a line balancing problem was considered for a special assembly line in an automotive factory. A new algorithm was required to deal with balancing an assembly line which consisted of the same job which must be performed by more than one worker at the same time. In this way, the new algorithm was expected to be effective in such a case that jobs were simultaneously completed in a parallel way. In order to measure effectiveness of the proposed algorithm, performance criteria were identified as total number of assembly station, total number of workers, and line productivity. As a result of the application of the proposed algorithm with taking into consideration factors such as cycle time, an allowable number of workers in an assembly station, and an allowable idle time of a worker, alternative solutions were determined in order to measure these criteria. However, these alternative solutions do not give any information about which of the solutions provide not only minimization of the number of assembly station and number of workers on the line but also maximize the line productivity at the same time. Hereby, a multi-response Taguchi method was applied in order to investigate levels of factors which directly affected system performance criteria.