Practical Performance Evaluation Research Articles

Dual-Interface Solar Evaporator with Highly-Efficient Thermal Regulation via Suspended Multilayer Design.

Facing the increasing global shortage of freshwater resources, this study presents a suspended multilayer evaporator (SMLE), designed to tackle the principal issues plaguing current solar-driven interfacial evaporation technologies, specifically, substantial thermal losses and limited water production. This approach, through the implementation of a multilayer structural design, enables superior thermal regulation throughout the evaporation process. This evaporator consists of a radiation damping layer, a photothermal conversion layer, and a bottom layer that leverages radiation, wherein the bottom layer exhibits a notable infrared emissivity. The distinctive feature of the design effectively reduces radiative heat loss and facilitates dual-interface evaporation by heating the water surface through mid-infrared radiation. The refined design leads to a notable evaporation rate of 2.83kg m-2 h-1. Numerical simulations and practical performance evaluations validate the effectiveness of the multilayer evaporator in actual use scenarios. This energy-recycling and dual-interface evaporation multilayered approach propels the design of high-efficiency solar-driven interfacial evaporators forward, presenting new insights into developing effective water-energy transformation systems.

Practical Implementation and Performance Evaluation of a Voice-Controlled Wheelchair System

Practical Implementation and Performance Evaluation of a Voice-Controlled Wheelchair System

Secrecy performance evaluation and enhancement of vehicle-to-vehicle communications in the presence of big vehicles

Despite its significant role in providing and developing reliable and safe intelligent transportation services, the Internet of Vehicles faces several challenges and security threats, such as co-channel interference (CCI), node self-interference (SI), and eavesdropping. This paper investigates the secrecy performance of vehicular networks in terms of their secrecy outage probability (SOP) and average secrecy capacity (ASC) in the presence of an eavesdropper. The legitimate vehicles are assumed to operate in full-duplex mode. Hence, the impacts of CCI and SI are considered for practical modeling and performance evaluation. Moreover, the wireless communications among vehicles are assumed to be either subjected to Nakagami-m fading or Nakagami-N-Gamma shadowed fading due to the existence of a big vehicle and its location. Accordingly, closed-form mathematical expressions are derived for the SOP and the ASC. Furthermore, a power allocation (PA) model is proposed to improve the secrecy performance by maximizing the derived ASC. The numerical results validate the derived expressions by demonstrating the impact of the channel condition, the secrecy data rate threshold, the SI cancellation capability at the legitimate destination, the location of the eavesdropper, the location of the big vehicle, and the strength of shadowing on the SOP and the ASC. Also, it is shown that the proposed PA model can significantly enhance the secrecy performance.

A new secondary battery technology: Electrode structure and charge–discharge mechanism of all-solid-state zinc-graphite batteries

Zinc is abundant in the Earth's crust, which contributes to its relatively low price. Magnesium-based silicate, as a solid electrolyte material, is environmentally friendly due to its enhanced thermal stability compared to liquid electrolytes. Introducing a graphite film can reduce both the manufacturing process and the cost of zinc-ion solid-state batteries. This study fabricated an all solid-state zinc-graphite battery using an evaporated zinc-gallium (Zn-Ga) alloy film as the negative electrode, pressed magnesium-based silicate powder as the solid electrolyte, and graphite film as the positive electrode. The experimental results revealed the microstructure characteristics of the positive electrode, electrolyte, and negative electrode materials, while the charging-discharging mechanism and practical performance evaluation confirmed the high-efficiency energy storage capabilities of the all-solid-state zinc-graphite battery.

Analysis of Monitoring and Evaluation Practices on Performance of Non-Governmental Organizations’ Project in Kiambu County, Kenya

Monitoring and evaluation is an essential practice in project management as it helps the project's scope to be defined, interventions to be established, and project managers to have an understanding of how project interventions would affect the project's implementation and objectives. The purpose for this study was to analyze monitoring and evaluation practices on the performance of Non-Governmental Organizations (NGOs) in Kiambu County in Kenya. The three main research objectives of this research are; the monitoring and evaluation planning practice; the monitoring and evaluation technical skills practice, and the participatory monitoring and evaluation practice on the performance of NGO’s in Kiambu County. This study utilized a descriptive investigative approach, with a sample size of 210 being non-governmental employees drawn from; Monitoring and evaluation officers, Project managers, and Stakeholder representatives out of a target population of 441. The tool for data analysis was the statistical package for social science version 26 and the results obtained were presented using tables and figures. The results of regression evaluation of monitoring and evaluation depicted a very strong connection between monitoring and evaluation planning practice and non-governmental organizations' project performance. The results of monitoring and evaluation of technical skill illustrated a positive connection between monitoring and evaluation of technical skill practice and non-governmental organizations' project performance. Further, the findings on Participatory monitoring and evaluation represented a confident connection between Participatory monitoring and evaluation practice and non-governmental organizations' project performance. Regression analysis results indicated that monitoring and evaluation planning practice; the monitoring and evaluation technical skills practice, and the participatory monitoring and evaluation practice positively and significantly impact the project performance of non-governmental organizational In Kiambu County, Kenya. This study therefore concluded that monitoring and evaluation planning practice; the monitoring and evaluation technical skills practice, and the participatory monitoring and evaluation practice positively and significantly impact the project performance of non-governmental organizational In Kiambu County, Kenya. This study recommends non-governmental organizational In Kiambu County, Kenya to pay particular attention to participatory monitoring and evaluation practice by focusing on those strategies that embrace participatory approaches, to create more inclusive and impactful M&E processes that contribute to sustainable development and positive change within communities. The findings in this research study will benefit, scholars, M&E practitioners, programme managers, government institutions, project stakeholders, and donor community in proper integration of the monitoring and evaluation practices for project performance.

Evaluation of Telephone Cardiopulmonary Resuscitation Performance in Current Practice in Saudi Arabia.

Out-of-hospital cardiac arrest (OHCA) is a global health problem with a low survival rate. Telephone cardiopulmonary resuscitation (T-CPR) guidance by emergency medical services (EMS) dispatchers can improve CPR performance and, consequently, survival rates. Accordingly, the American Heart Association (AHA) has released performance standards for T-CPR in current practice to improve its quality. However, no study has examined T-CPR performance in Saudi Arabia. Therefore, this study aims to evaluate T-CPR performance in the Saudi Arabian EMS system. A retrospective observation of OHCA calls in current practice was conducted in Riyadh, Saudi Arabia. OHCA calls were reviewed to identify those that met the selection criteria. Variables collected included return of spontaneous circulation (ROSC), OHCA recognition rate, time from EMS call receipt to location acquisition, to OHCA recognition and to commencement of CPR. A total of 308 OHCA cases were reviewed, and 100 calls were included. ROSC was identified in 10% of the included calls. OHCA was correctly recognized in 62% of the calls. The time to OHCA identification and CPR performance from EMS call receipt were found to be 303 s and 367 s, respectively. T-CPR performance in Saudi Arabia is below AHA standards. However, this is similar to what has been reported in the literature. Avoiding any unnecessary call transfer during OHCA calls and prompt identification of callers' locations could improve T-CPR performance.

Practical Improvement and Performance Evaluation of Road Damage Detection Model using Machine Learning

The social infrastructure, including roads and bridges built during period of rapid economic growth in Japan, is now aging, and there is a need to strategically maintain and renew the social infrastructure that is aging. On the other hand, road maintenance in rural areas is facing serious problems such as reduced budgets for maintenance and a shortage of engineers due to the declining birthrate and aging population. Therefore, it is difficult to visually inspect all roads in rural areas by maintenance engineers, and a system to automatically detect road damage is required. This paper reports practical improvements to the road damage model using YOLOv5, an object detection model capable of real-time operation, focusing on road image features

Analytical Model for the Design of Permeable Reactive Barriers Considering Solute Transport in a Dual-Domain System

A permeable reactive barrier (PRB) is an effective groundwater in situ remediation technology, and the design methods used for PRBs are significant in ensuring that they meet remediation goals. Steady-state analytical solutions are an effective tool to provide conservative and simple design methods. A steady-state analytical solution is proposed to describe organic contaminant transport through the PRB and aquifer in a PRB and cut-off wall system. The proposed analytical solution may serve as an effective tool to provide conservative and simple design methods. The shape factor (S) is introduced at the PRB-aquifer interface to investigate the effects of a PRB’s layout forms on its performance. The results show that the relative contaminant concentration at the point of compliance for a PRB with S=8 is 11 orders of magnitude larger than that without considering the shape factor. Effects of degradation, dispersion, and advection on PRB design are subjected to dimensionless analysis. Dimensionless analysis shows that degradation plays a key role in decreasing contaminant concentration in the PRB. In addition, increasing advection may promote contaminant transport from the source to the aquifer. Simplified solutions to estimate PRB thickness and source remediation time are derived for the practical design and performance evaluation of the PRB system.

Lessons Learned from a Novel Three-year Longitudinal Stepwise "Residents-as-Teachers" Program.

Most residents-as-teachers (RaT) programs are delivered over days to weeks without comprehensive evaluation, and stepwise approaches have rarely been applied to RaT activities. This study aimed to depict the implementation experience and evaluate the effectiveness of a novel longitudinal three-year, stepwise RaT program. The longitudinal RaT program included three once yearly face-to-face courses according to the different teaching roles of the residents. To evaluate the effectiveness of the new longitudinal program, we designed a randomized controlled study for first-year residents of all specialties in one medical center. The effectiveness was evaluated by the objective structured teaching exercise (OSTE), feedback from participants and medical students, and evaluation of clinical practice performance by program directors. A total of 35 (37.6%) of 93 residents participated in this study, and 13 (37.1%) of all enrolled residents completed all three-year courses, including seven for the longitudinal program and six for the traditional. The serial OSTE revealed significantly higher scores in the longitudinal group in the second and third years (13.43 vs. 9.50, p=0.001 and 14.29 vs. 10.33, p=0.015). Satisfaction was higher when advanced topics were taught in the second and third years compared with those taught in the first year (4.43 vs. 3.89, p=0.02). The feedback from medical students was similar between the two groups, and the evaluation from program directors revealed insignificantly better clinical performance among the longitudinal course participants. It is challenging to conduct a multi-year longitudinal RaT program on young residents. Nevertheless, this longitudinal program was potentially associated with better learning retention and higher satisfaction and worthy to be promoted.

Investigation of the Global Structural Behavior of the Prefabricated Shoring System Considering Structural Details

This study aims to investigate the structural behavior and load-carrying capacity of prefabricated shoring systems. The structural behavior and performance of shoring systems are influenced by the buckling of vertical members, where the compressive force acts as the main load. The buckling strength of a vertical member is sensitive to not only the material and geometrical properties of members but also the connection details between members, presence or absence of braces, and stiffness ratio between members. Therefore, in this study, the structural behavioral characteristics of the individual post member and the entire system are investigated by considering the structural details through eigenvalue and nonlinear finite element analyses. On the basis of the analytical studies, it was confirmed that the boundary condition of the vertical member, rotational and horizontal stiffnesses, and eccentricity condition of the end, which are directly affected by the compressive force acting on the prefabricated shoring system, have a direct effect on the elastic buckling strength. In addition, it was determined that factors such as whether the braces were installed, rotational stiffness of the vertical–horizontal member connection, and the number of installation stages affected the overall strength of the structure. According to the structural analysis results, the assembled structure was reduced by 92.9% and 82.2% compared to the elastic buckling strength of a single member as the height increased to two and three stories. In addition, when the bracing member was not installed, 12.1% and 23.6% strength reduction was confirmed as the elastic buckling strength increased by two and three stories compared to the case where the bracing member was installed. Consequently, the necessity of a whole structural performance evaluation technique was confirmed for a more practical structural performance evaluation.

DC-AC Converter with Dynamic Voltage Restoring Ability Based on Self-Regulated Phase Estimator-DQ Algorithm: Practical Modeling and Performance Evaluation

A self-regulated phase estimator (SRPE)-based DQ algorithm for a DC-AC converter with dynamic voltage restoring (DVR) ability is presented in this paper. When compared to the conventional phase-locked loop (PLL), the provided controller can significantly reduce phase distortions and low-order harmonics from the load voltage while attaining quicker dynamic response. Furthermore, the fundamental attribute of the load voltage allows the integrated DC-AC converter to operate at a consistent frequency eliminating frequency oscillations. The SRPE is utilized primarily in the DQ control theory as the reference voltage generator which can compensate for the grid voltage. SRPE has good band-pass filtering properties and a mathematically simple structure that can thoroughly attenuate voltage imbalance and has quick dynamic response. The SRPE has been made to be frequency-adaptive using a damping factor and robust grid frequency estimation. The SRPE can maintain the fundamental frequency at 50 Hz and keep the total harmonic distortions (THD) within the 5% limit even during grid disruptions. The DC-AC converter and SRPE-DQ’s stability are thoroughly examined. The experiment is carried out to show the efficacy of the suggested complete control system. There are also comparative simulation studies to show the benefits of the suggested technique. The results reveal that the suggested approach can immediately identify and correct for any grid voltage imbalance while also assisting in maintaining the constant voltage at the load side despite voltage sag/swell and distortions.

A New Radio Frequency Distortion Dynamic Range Index for Performance Evaluation

Dynamic range and spurious-free dynamic range are two of the most critical performance indexes in the field of radio frequency (RF). However, the definitions of both the indexes are ambiguous, and their characterization ability is insufficient, resulting in unfair, and even mutually incompatible, performance evaluation in practice. In this study, a new index named radio frequency distortion dynamic range and its corresponding evaluation method are proposed to achieve a fair and detailed dynamic range evaluation by unifying the existing definitions and improving the performance resolution ability. First, the sliding threshold selection method is introduced to replace the classification-based method of dynamic range definition to characterize more details of the dynamic range. Second, a dynamic range evaluation method of “performance body” is proposed to obtain a more comprehensive evaluation by generalizing the current evaluation from being based on a single condition to the one based on scanning critical conditions. Experiments show that the proposed radio frequency distortion dynamic range index with the proposed evaluation method reduces the ambiguity of dynamic range evaluation and can distinguish the performance difference that the current indexes cannot do.

Examination of the Reading Comprehension Skills of Good and Poor Readers in the Dimension of Reading Components Developed by a Reading Skills Assessment Tool

The aim of this study is to develop a Reading Skills Assessment Tool (RSAT) for 2nd, 4th, 6th and 8th grade readers and to assess if there is a significant difference between the decoding and fluent reading skills of good and poor comprehenders. First, validity and reliability studies of the RSAT, which includes the dimensions of decoding, fluent reading, and reading comprehension, were conducted in this direction. The RSAT was finalized with the data collected from 840 participants in validity and reliability studies. Following this, the reading comprehension scores of 150 participants at each grade level were divided into lower and upper 27% groups, and groups with good and poor comprehenders were determined. Then, the differences in the decoding and reading fluency results of the good and poor comprehenders were studied. The results revealed that the decoding and fluency reading performances of good comprehenders were considerably superior to those of the group with poor comprehenders, and the results were reviewed in light of the relevant literature. Consequently, good comprehenders performed better than poor comprehenders in decoding (syllable reading pace, real word reading pace and pseudoword reading accuracy) and fluent reading (correct number of words read per minute). With the research, a formal tool for evaluating reading skills has been added to the Turkish literature, and it has contributed to the elimination of an important limitation in this field. RSAT can be used effectively by experts in scientific studies and by teachers in the evaluation of student performance in practice. In addition, it was emphasized that good and poor readers perform differently in all aspects of reading, and that it is crucial to prevent future problems by conducting the necessary evaluations and interventions at the outset of reading instruction.

Development of a Composite Project Performance Index for the New Engineering Contract (NECPPI) of construction projects in Hong Kong: a Delphi study

Over the past three decades, a basket of research studies on New Engineering Contract (NEC) has been conducted in the construction management discipline. In fact, there is adequate evidence that an increasing number of client organisations have been adopting a NEC approach to undertake their building and construction projects both locally and worldwide during the last three decades. With the perceived benefits that NEC brings about, research into the Key Performance Indicators (KPIs) to evaluate the success of NEC projects in construction becomes all the more important because it can help set a benchmark for measuring the overall performance level of NEC projects. Although there are some related studies and papers on this research area, few, if any, comprehensive and systematic studies have focused on developing a comprehensive, objective, reliable and practical performance evaluation model for NEC projects. A benchmarking model has been developed in this paper using the Delphi survey technique to objectively measure the performance of the Engineering and Construction Contract (ECC) of NEC projects in Hong Kong based on a consolidated KPIs’ conceptual framework for NEC projects. Four rounds of Delphi questionnaire survey were conducted with 16 construction experts in Hong Kong and the United Kingdom. The results revealed that the top seven weighted KPIs to evaluate the success of NEC projects in Hong Kong include: (1) time performance; (2) safety performance; (3) quality performance; (4) development of mutual trust and cooperation; (5) cost performance; (6) equitable risk management mechanism; and (7) project team satisfaction. A statistically significant consensus on the top seven weighted KPIs was also obtained. Finally, a composite Project Performance Index for NEC projects (NECPPI) in Hong Kong was derived to provide an all-round assessment of NEC project performance. Different NEC projects can now be assessed on the same basis for benchmarking purposes. Construction senior executives and project managers can thus use the Index to measure, evaluate and improve the performance of their NEC projects to strive for construction excellence. Although the NECPPI was established locally in Hong Kong, the research methodology could be replicated in other parts of the world such as the United Kingdom or other European countries to produce similar indices for international comparisons. Such and extension would aid the understanding of managing NEC projects across different geographic locations.

Attribute Service Performance Index Based on Poisson Process

The purpose of a shop enhancing customer satisfaction is to raise its total revenue as the rate of customer purchases in the shop increases. Some studies have pointed out that the amount of customer arrival at a shop is a Poisson process. A simple and easy-to-use evaluation index proposed for the Poisson process with the attribute characteristic will help various shops evaluate their business performance. In addition, developing an excellent and practical service performance evaluation method will be beneficial to the advancement of shop service quality as well as corporate image, thereby increasing the profitability and competitiveness of the shop. As the surroundings of the internet of things (IoT) are becoming gradually common and mature, various commercial data measurement and collection technologies are constantly being refined to form a huge amount of production data. Efficient data analysis and application can assist enterprises in making wise and efficient decisions within a short time. Thus, following the simple and easy-to-use principle, this paper proposes an attribute service performance index based on a Poisson process. Since the index had unknown parameters, this paper subsequently figured out the best estimator and used the central limit theorem to derive the confidence interval of the service efficiency index based on random samples. Then, we constructed the membership function based on the α-cuts of the triangular shaped fuzzy number. Finally, we came up with a fuzzy testing model based on the membership function to improve the accuracy of the test when the sample size is small in order to meet enterprises’ needs for quick responses as well as reducing the evaluation cost.

Direct evaluation method for load-deformation curve of precast prestressed concrete frame with different tendon forces

To establish a more accurate, flexible, and practical performance evaluation method for unbonded precast prestressed concrete (PCaPC) frames, a macro model was illustrated based on the exterior beam–column sub-assemblages of unbonded PCaPC frames, which considers different tensile forces of the post-tensioned tendons (i.e. unsymmetrical tendon forces) and high-strength concrete. Based on the macro model, closed-form equations of beam axial shortening were provided by precisely considering the deformation compatibility and force equilibrium conditions along the beam. In this study, the iteration method for the comprehensive evaluation of different performance limit states, as well as the load–deformation relationship of the beam–column sub-assemblages, were constructed and simplified. Accuracy and superiority of the proposed evaluation methods were verified by comparison with experimental data and evaluation results of previous methods. Both damage tolerance and self-centering performance of unbonded PCaPC frames can be more accurately measured by the proposed methods. Meanwhile, the consideration of unsymmetrical tendon forces makes the methods more flexible for different types of unbonded PCaPC frames. In addition, parametric study was conducted to understand the effects of critical design parameters on the performance limits. Preliminary design advices were given to show the application potential of this study.

Asynchronous substructuring method with alternating local and global iterations

Until now, almost all investigations of asynchronous iterations within domain decomposition frameworks targeted methods of the parallel Schwarz type. A first, and sole, attempt to deal with a primal substructuring framework resulted in an asynchronous substructuring method where relaxation occurs simultaneously on the subdomains and on the interface between them, which therefore corresponds to a substructured relaxation scheme defined on the whole global domain. In this paper, we propose a Gauss–Seidel kind of improvement consisting of alternating between relaxation on the interface and relaxation on the subdomains, hence, always using the latest solutions in the subdomains when updating the solution on the interface, which is feasible at no additional cost. It turns out that one particular case of our general alternating relaxation scheme corresponds to an asynchronous substructuring method with iterations fully defined on the subdomains’ interface, and where only local Schur complements are involved. Practical performance evaluation on both standard Poisson’s and linear elasticity problems has been conducted using a multi-node parallel computational platform with up to 720 CPU cores.

Noise invariant partial discharge classification based on convolutional neural network

Partial discharge (PD) pattern recognition is essential since it can help to identify the nature of the insulation defect. Numerous machine learning models have been utilized for PD classification applications in the past. However, traditional machine learning models rely on manual feature extraction to obtain training data. They are usually trained using clean PD data measured in the laboratory but are expected to work on-site where some degree of interference or noise is expected. When tested using clean PD data, most machine learning models can easily achieve above 90% accuracy. However, when tested using PD data overlapped with noise, classification accuracy reduces significantly. In this work, the development of a convolutional neural network (CNN)-based PD classification system using transfer learning was proposed. In order to achieve a more practical performance evaluation, a modified 10-fold cross-validation procedure was used where the CNN-based PD classifier was trained using clean PD data but tested using PD data that has been overlapped by noise. The results showed that CNN-based PD classifier was able to achieve up to 16.90% higher classification accuracy under noise contamination compared to traditional machine learning with manual feature extraction. This shows that the proposed method was able to retain higher classification accuracy in the presence of noise.

Current ERCP practice in Belgium: the BSGIE survey.

Data on procedural outcome and quality of endoscopic retrograde cholangiopancreatography (ERCP) in Belgian practice are scarce. The aim of this study is to assess current status of ERCP-performance in Belgium. National multi-institutional survey (online questionnaire) among members of the Belgian Society of Gastrointestinal Endoscopy (BSGIE), conducted in the period June-August 2018. The RIZIV/INAMI provided real-life data on the total number of ERCPs performed in Belgium. Forty-five responders completed the survey (for 43 centers performing ERCP), providing information for 8368 ERCPs performed in 45% (43/95) of institutions performing ERCP in Belgium. Fifty-eight percent of centers performed > 100 ERCPs/year and 7% of centers (n=3) performed < 50 ERCPs/year. According to the RIZIV/INAMI data, low case-volume centers are underrepresented in this survey. The most common ERCPindication was stone extraction (52%). 74% of endoscopists had more than 10 years of experience in performing ERCP. The majority of centers had their own written protocol (84%) for microbiological duodenoscope surveillance. Monitoring of cannulation rate and post-ERCP pancreatitis (PEP) was only performed in a minority of centers (30%). The majority of centers (76%) provided verbal informed consent relating to the ERCP-procedure ; a minority also requested a written informed consent (23%). 65% of centers systematically use NSAIDs for PEP prophylaxis. This is the first survey of ERCP performance in Belgium. There were wide variations in practice. Adherence to key performance measures and measurement and evaluation of ERCP performance in daily practice at center and endoscopist level are not uniformly widespread.

Data-Driven Characterization and Modeling of Web Map System Workload

Every month, billions of users access Web Map Systems (WMSs), such as Google Maps, to visualize geospatial data. A large number of users and the huge amount of data demanded by these applications make the design and development of WMSs a challenging task, especially in terms of performance and scalability. In this context, workload generators become crucial tools, as they help system administrators to plan the capacity of WMSs and design provisioning strategies for peak load scenarios. However, little is known about the workload patterns generated by WMS users. In this work, we use data anonymously collected from sessions of a client application of Google Maps to devise a model that describes how users of desktop terminals navigate in a Web map. Based on this model, we implement a workload generator called MUSeGen. We compare the workload patterns generated by MUSeGen against the workload patterns found in real data. Results show that MUSeGen generates synthetic traces whose navigation patterns closely match those found in real data. We also compare MUSeGen against HELP, a workload generator built upon previous findings on empirical knowledge on the usage of WMSs. Results show that the number of issued operations per session in HELP is, on average, four times lower than that in MUSeGen and the number of tiles requested is, on average, twice lower than that in our tool. In addition, navigation patterns in HELP are much simpler than in MUSeGen. These findings support the conclusion that MUSeGen produces more realistic workloads than HELP. To illustrate how such differences affect performance evaluation in practice, we carry out a performance evaluation of a real WMS under workloads generated by HELP and MUSeGen. Our evaluation shows that the system capacity under HELP is three times less than that obtained under MUSeGen, highlighting the value of MUSeGen.