System-level Evaluation Research Articles

A Framework for UWB-Based Communication and Location Tracking Systems for Wireless Sensor Networks

Ultra wideband (UWB) radio technology is nowadays one of the most promising technologies for medium-short range communications. It has a wide range of applications including Wireless Sensor Networks (WSN) with simultaneous data transmission and location tracking. The combination of location and data transmission is important in order to increase flexibility and reduce the cost and complexity of the system deployment. In this scenario, accuracy is not the only evaluation criteria, but also the amount of resources associated to the location service, as it has an impact not only on the location capacity of the system but also on the sensor data transmission capacity. Although several studies can be found in the literature addressing UWB-based localization, these studies mainly focus on distance estimation and position calculation algorithms. Practical aspects such as the design of the functional architecture, the procedure for the transmission of the associated information between the different elements of the system, and the need of tracking multiple terminals simultaneously in various application scenarios, are generally omitted. This paper provides a complete system level evaluation of a UWB-based communication and location system for Wireless Sensor Networks, including aspects such as UWB-based ranging, tracking algorithms, latency, target mobility and MAC layer design. With this purpose, a custom simulator has been developed, and results with real UWB equipment are presented too.

The promise of downlink MU-MIMO for high-capacity next generation mobile broadband networks based on IEEE 802.16 m

The dramatic increase of the demand for mobile broadband services poses stringent requirements on the performance evolution of currently deployed mobile broadband networks, such as Mobile WiMAX Release 1 and 3GPP LTE Release 8. Although the combination of single-user multiple-input multiple-output (SU-MIMO) and orthogonal frequency division multiple access (OFDMA) provide the appropriate technologies for improving the downlink performance of third generation (3G) code division multiple access (CDMA)-based mobile radio systems and, thus, address the current mobile internet requirements, a fundamental paradigm shift is required to cope with the constantly increasing mobile broadband data rate and spectral efficiency requirements. Among the different technologies available for making the paradigm shift from current to next-generation mobile broadband networks, multiuser MIMO (MU-MIMO) constitutes the most promising technology because of its significant performance improvement advantages. In this article, we analyze the performance of MU-MIMO under a multitude of deployment scenarios and system parameters through extensive system-level simulations which are based on widely used system-level evaluation methodologies. The target mobile broadband system used in the simulations is IEEE 802.16 m which was recently adopted by ITU-R as an IMT-Advanced technology along with 3GPP LTE-Advanced. The results provide insights into different aspects of MU-MIMO with respect to system-level performance, parameter sensitivity, and deployment scenarios, and they can be used by the mobile broadband network designer for maximizing the benefits of MU-MIMO in a scenario with specific deployment requirements and goals.

Evaluating systems change in a juvenile justice reform initiative

Evaluating comprehensive, interagency initiatives to reform human services systems presents substantial challenges to traditional research models. Outcomes are observed at the system level rather than the individual level, and the validity of study results may be challenged on a variety of dimensions, particularly small sample sizes and measurement error. We report the results of a cross-site evaluation of the first phase of Reclaiming Futures, a five-year effort to improve services and interventions for justice-involved youth in 10 communities across the United States. We present the evaluation findings and discuss implications for similar research endeavors. The methods used in this study may be useful for other system-level evaluation efforts. A social network analysis analyzes changes in the size, density, and cohesiveness of stakeholder networks. Bivariate models test for associations between Reclaiming Futures implementation and key stakeholder perceptions of effective system change. Multivariate models are used to explore selection effects on item response. In general, we find positive correlations between successful implementation of Reclaiming Futures and indicators of effective and efficient system change.

Evaluating Carbon Nanotube Global Interconnects for Chip Multiprocessor Applications

In ultra-deep submicrometer (UDSM) technologies, the current paradigm of using copper (Cu) interconnects for on-chip global communication is rapidly becoming a serious performance bottleneck. In this paper, we perform a system level evaluation of Carbon Nanotube (CNT) interconnect alternatives that may replace conventional Cu interconnects. Our analysis explores the impact of using CNT global interconnects on the performance and energy consumption of several multi-core chip multiprocessor (CMP) applications. Results from our analysis indicate that with improvements in fabrication technology, CNT-based global interconnects can significantly outperform Cu-based global interconnects.

A high-throughput microplate assay for simultaneous colorimetric quantification of multiple enzyme activities in soil

A high-throughput assay was developed for the simultaneous quantification of various soil enzyme activities using p-nitrophenyl substrates. The average coefficients of variance ( n = 20) for assaying activities of N-acetyl-β- d-glucosaminidase, α- d-glucosidase, β- d-glucosidase, α- d-galactosidase, and β- d-galactosidase were 10, 15, 12, 18, and 16%, respectively. This assay makes it possible for system-level evaluations that demand simultaneous examination of multiple enzyme activities in a large number of soils within hours of sampling.

System-level evaluation of dicyandiamide (DCD) for improved environmental outcomes on New Zealand dairy farms

Nitrification inhibitors are an important mitigation practice for nitrate leaching since they reduce leaching loads and can potentially increase farm profit through promoting pasture production.

Does outcome feedback make you a better emergency physician? A systematic review and research framework proposal

The organization of emergency medical care limits the ability of emergency physicians to know the outcomes of most of their patients after the patients leave the emergency department. This lack of outcome feedback may hinder the practice of emergency medicine (EM) by preventing "calibration" of the decision tools of practitioners. We sought to determine what is currently known about outcome feedback in EM, including its incidence, impact and modifiers. We searched the following databases: PreMEDLINE, MEDLINE, EMBASE, CINAHL, CENTRAL, PsycINFO, DARE, Health Technology Assessment Database and AMED. We performed manual searches on abstract databases, reference lists, various health information and research websites, and nonindexed journals. Selection entailed a 2-step screening pro cess to exclude articles not pertaining to outcome feedback in EM. Our search yielded 1128 bibliographic records, from which screening identified 7 relevant reports: 5 surveys, 1 system level evaluation and 1 intervention trial. All studies were found to have "inadequate" or "unable to assess" reporting and study quality. Systems for outcome feedback to EM residents have been increasingly available since 1984, though they are perceived to be inadequate. Commonly used mechanisms for outcome feedback include automatic routing of discharge summaries, case conferences for admitted patients and telephone calls to patients or families for discharged patients. With respect to attending emergency physicians, no conclusions or clinical recommendations can be made given the level of available evidence. The potential importance of outcome feedback remains, at this time, underevaluated. We propose a research framework, and hypothesize that increasing outcome feedback would increase emergency physician diagnostic accuracy, therapeutic outcomes, clinical efficiency and job satisfaction. Future research in this area should include surveys and focus groups, as well as simulated or real-world intervention trials.

Computationally Efficient MIMO HSDPA System-Level Modeling

Multiple-inputmultiple-output (MIMO) techniques are regarded as the crucial enhancement of todays wireless access technologies to allow for a significant increase in spectral efficiency. After intensive research on single link performance, the third Generation Partnership Project (3GPP) integrated a spatial multiplexing scheme as MIMO extension of High-Speed Downlink Packet Access (HSDPA). Despite the scientific findings on the link-level performance of MIMO techniques, many questions relevant for the design and optimization of cellular networks remain unanswered. In particular, it has to be identified whether, and to which amount, the predicted MIMO link-level performance gains can be achieved in an entire network. In this paper, we present a computationally efficient link-to-system level model for system-level evaluations of MIMO HSDPA and an exemplary embedding in a MATLAB-based system-level simulator. The introduced equivalent fading parameter structure allows for a semianalytic physical-layer abstraction with high prediction accuracy and simultaneous moderate complexity.

Enhanced control performance of a piezoelectric—hydraulic pump actuator for automotive transmission shift control

In this research, a piezoelectric—hydraulic pump (PHP) actuator is synthesized for an automatic transmission (AT) test bed to demonstrate its potentials as a controllable power-by-wire actuator. This research expands from the previous investigations by enhancing the control performance of the PHP actuator developed for AT and bringing the study to the system level. Actuation force-tracking control using an on-site force transducer is proposed and a fill volume control strategy utilizing the AT turbine acceleration information is explored. The system level evaluation of shift performance is performed to demonstrate the effectiveness of the proposed enhancements through a hardware-in-the-loop simulation environment.

Valutare gli studenti per valutare il sistema: una esperienza della Provincia di Varese

- The article presents the main results of a system level evaluation of learning outcomes concerning compulsory Vocational Training (VT) 3-years courses final formal examinations. This evaluation, carried out by the Education and Vocational Training Department of an italian Province (Varese), specifically deals with the use of single student learning standardized outcomes as a crucial component - if properly designed, managed and processed - of the evaluation of a local institutional VT system as a whole. This is quite a challenging task in Italy due both to the territorial differences existing in VT policies and institutional responsibilities and to the weakness of system evaluation culture, models and experiences in VT specifically and in education in general. The evaluation, conducted with the supervision of the two authors, will be presented and briefly discussed mainly by a methodological perspective. It will focus on the way in which learning contexts, training contents and trainees characteristics have been included into the evaluative analysis as factors potentially able: a) to explain, at a system level, the learning outcomes of the students; b) to offer the local stakeholders a comprehensive set of information and evidences to be used for the improvement of VT policies, programmes and single interventions.Key words: educational and vocational training, learning outcomes assessment, system evaluation, comparison, explicationParole chiave: istruzione e formazione professionale, valutazione di sistema, valutazione degli apprendimenti, comparazione, spiegazione

Concurrent dual-band SiGe HBT power amplifier for Wireless applications

This paper presents an investigation of a concurrent low-cost dual-band power amplifier (PA) fabricated in SiGe technology, able to simultaneously operate at two frequencies of 2.45 and 3.5-GHz, including an evaluation of its system level performance potentiality. Taking into account the technology novelty and the lack of device characterization and modeling, a hybrid (MIC) approach has been adopted both for a fast prototyping of the PA and for the evaluation of the device potentiality based on an extensive linear and nonlinear characterization. The comparison of PA performance in single-band or concurrent mode operation will be presented. In particular, the measured PA prototype shows an output power of 17.2 and 17-dBm at a 1-dB compression point, at 2.45 and 3.5-GHz, respectively, for CW single-mode operation, with a power added efficiency around 20%. System-level analysis predicts that, when the PA is operated under the 20-MHz Orthogonal Frequency-Division Multiplexing (OFDM) concurrent signals, the maximum output power levels to maintain the Error Vector Magnitude (EVM) within 5% are 11 and 3.5-dBm at 2.45 and 3.5-GHz, respectively. Moreover, new concepts and possible new system architectures for the development of the next generation of the multi-band transceiver front-end will be provided with an extensive system-level evaluation of the amplifier.

System Level Evaluation of Innovative Coded MIMO-OFDM Systems for Broadcasting Digital TV

Single-frequency networks (SFNs) for broadcasting digital TV is a topic of theoretical and practical interest for future broadcasting systems. Although progress has been made in the characterization of its description, there are still considerable gaps in its deployment with MIMO technique. The contribution of this paper is multifold. First, we investigate the possibility of applying a space-time (ST) encoder between the antennas of two sites in SFN. Then, we introduce a 3D space-time-space block code for future terrestrial digital TV in SFN architecture. The proposed 3D code is based on a double-layer structure designed for intercell and intracell space time-coded transmissions. Eventually, we propose to adapt a technique called effective exponential signal-to-noise ratio (SNR) mapping (EESM) to predict the bit error rate (BER) at the output of the channel decoder in the MIMO systems. The EESM technique as well as the simulations results will be used to doubly check the efficiency of our 3D code. This efficiency is obtained for equal and unequal received powers whatever is the location of the receiver by adequately combining ST codes. The 3D code is then a very promising candidate for SFN architecture with MIMO transmission.

SIMULTANEOUS TIME-FREQUENCY MODELING OF ULTRA-WIDEBAND ANTENNAS BY TWO-DIMENSIONAL HERMITE PROCESSING

This paper proposes an approximate space-time-frequency field representation for directive Ultra-wideband antennas useful to be introduced into a system-level evaluation tool. Based on the observation that the very near field collected on a plane close to the antenna exhibits a compact support, such a field is processed in the time domain by the two-dimensional Hermite transform. This approach permits to simultaneously express the antenna impulse response and the transfer function by semi-analytical formulas. The theory is demonstrated by numerical examples which highlights that good representations of complex antennas can be achieved by a small set of associate Hermite functions.

System-level performance evaluation of UMTS with multi-service

In this paper, we perform a simulative evaluation of Universal Mobile Telecommunications System (UMTS) with multi-service via Network Simulator 2 for a newly built scenario. We change the scenario environment parameters, such as link delay, speed of User Equipment (UE) and interference traffic rate, to show how diverse services are affected. The results with respect to bandwidth, end-to-end delay, handoff latency, packet loss and delay jitter are presented to provide thorough investigation of UMTS under various services. Additionally, we discuss the impact of co-channel interference and compare the performance in the situation with and without interference. Based on the results from simulations, we have drawn conclusions that (i) end-to-end delay and handoff latency are proportional to link delay so that they are not severely influenced by different services for a high value of link delay, (ii) the number of packet loss is not directly related to link delays or UE's speed, (iii) UE's speed does not affect the performance obviously, (iv) co-channel interference exists in UMTS, and so on.

Capacity Improvement of Multihop Inter-Vehicle Communication Networks by STBC Cooperative Relaying

In this paper, we evaluate the effect of space-time coded cooperative relaying technique in multihop inter-vehicle communication (IVC) networks. The IVC systems have an issue that communication links are often blocked by obstacles such as heavy vehicles. The breakage of a radio link in multihop connections may significantly decrease the system throughput in multihop IVC networks. It is demonstrated through system-level evaluations that the cooperative relaying can offer remarkable capacity enhancement by exploiting multi-route diversity and overcoming accidental link breakage resulting from frequent topological changes.

System-level performance evaluation of reconfigurable processors

Reconfigurable architectures that tightly integrate a standard CPU core with a field-programmable hardware structure have recently been receiving increased attention. The design of such a hybrid reconfigurable processor involves a multitude of design decisions regarding the field-programmable structure as well as its system integration with the CPU core. Determining the impact of these design decisions on the overall system performance is a challenging task. In this paper, we first present a framework for the cycle-accurate performance evaluation of hybrid reconfigurable processors on the system level. Then, we discuss a reconfigurable processor for data-streaming applications, which attaches a coarse-grained reconfigurable unit to the coprocessor interface of a standard embedded CPU core. By means of a case study we evaluate the system-level impact of certain design features for the reconfigurable unit, such as multiple contexts, register replication, and hardware context scheduling. The results illustrate that a system-level evaluation framework is of paramount importance for studying the architectural trade-offs and optimizing design parameters for reconfigurable processors.

Future Utilization and Optimal Investment Strategy for Inland Waterways: New Model from U.S. Army Corps of Engineers to Assist Policy Makers

For nearly three decades, the U.S. Army Corps of Engineers (the Corps) has been measuring incremental system navigation transportation costs for proposed infrastructure investments in search of the National Economic Development (NED) plan: local optimization in a system-level evaluation. The increasingly complex and sophisticated analysis requires the development of additional modeling modules. The traditional analysis assumed a most-likely traffic forecast and a set investment timing. Cost-benefit analyses on various alternatives were compared to determine the without-project condition and the recommended with-project NED plan. Sensitivity analyses of traffic forecasts and investment timing were done on the with-project plan. The second generation of analysis factored in the impacts of scheduled chamber closure differences between alternatives, and the third generation of analysis factored in the impacts of unscheduled ones. The goal is to be able to optimize investments simultaneously across a system (not just investments at one site) under a series of forecast scenarios while capturing structural reliability differences (scheduled and unscheduled closures). As the demands of the analysis increased, there was a need to consolidate and dynamically link the various models and techniques developed over the years and to develop new techniques to simultaneously manage investment permutations and automatically select optimal investment plans; the desire was to perform system optimization in a system-level evaluation. The innovative analysis techniques and relational database management structure of the new Ohio River Navigation Investment Model are introduced, as is a set of flexible, integrated analysis modules that move the Corps closer to these ideals.

Route guidance and information systems

This paper reviews key aspects of route guidance and information systems (RGISs), which disseminate to drivers messages with information and recommendations intended to assist their route choice decisions. It first summarizes the major features that characterize and distinguish different RGIS designs. An important distinction exists between non-predictive and predictive systems. In the former, guidance messages are based on measurements or estimates of prevailing network conditions, while, in the latter, messages are derived from forecasts of future conditions. For predictive systems, the key issue is consistency: ensuring that drivers’ reactions to guidance derived from forecasts do not invalidate those forecasts. It is shown that the determination of consistent guidance must be model based and can be formulated as a fixed-point problem. The modelling of driver response to guidance is a relatively new subject; the paper surveys the main issues, and relates these to the user-and system-level evaluation of RGISs. A final section identifies some areas of current research.

Route guidance and information systems

This paper reviews key aspects of route guidance and information systems (RGISs), which disseminate to drivers messages with information and recommendations intended to assist their route choice decisions. It first summarizes the major features that characterize and distinguish different RGIS designs. An important distinction exists between non-predictive and predictive systems. In the former, guidance messages are based on measurements or estimates of prevailing network conditions, while, in the latter, messages are derived from forecasts of future conditions. For predictive systems, the key issue is consistency: ensuring that drivers’ reactions to guidance derived from forecasts do not invalidate those forecasts. It is shown that the determination of consistent guidance must be model based and can be formulated as a fixed-point problem. The modelling of driver response to guidance is a relatively new subject; the paper surveys the main issues, and relates these to the user-and system-level evaluation of RGISs. A final section identifies some areas of current research.

The utilization of the logic model as a system level planning and evaluation device

Many questions exist about how to evaluate the impacts of local human services delivery systems. This paper presents a potential mechanism for such evaluations and describes the experiences of a large, urban United Way. The mechanism focuses on a tool called the logic model. A description of the local United Way planning and evaluation process and how this process was enhanced through the utilization of the logic model is provided. The United Way experience suggests that the logic model may have application to planning domains where the desire is to achieve long term social objectives through the implementation of multiple, shorter term interventions. The logic model provides a mechanism and conceptual basis for identifying and measuring system impacts.