• Title/Summary/Keyword: performance objective

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Estimation of Error Performance for Digital Satellite Communication (디지털 위성통신 시스템에서의 오류 성능 추정)

  • Yeo, Sung-Moon;Kim, Soo-Young
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.45 no.2
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    • pp.52-59
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    • 2008
  • Recommendation ITU-R S.1062 specifies the performance of digital satellite systems. The performance objectives were given in terms of bit error probability divided by the average number of errors per burst versus percentage of time. This performance objective is highly dependent on the forward error correction(FEC) coding schemes used in the system. This implies that we need an effective way of estimating the error performance of a system by the given FEC scheme. In this paper, we derive theoretical formula to estimate performance measure of digital satellite systems defined in Recommendation ITU-R S.1062. We demonstrate various estimation results, and verify them by comparing to the simulation results.

Implementation of RPMS, the Evaluation and Management Tool for Urban Residential Performance and Possible Applications (도시주거지역 거주성 및 거주성능의 평가 및 관리도구 RPMS의 구현과 활용제안)

  • Park, Soo-Hoon;Lee, Sang-Hyun
    • Korean Journal of Computational Design and Engineering
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    • v.15 no.1
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    • pp.51-59
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    • 2010
  • People evaluate urban residential regions quite frequently and sensitively, considering issues such as locations or ease of use of in-site facilities or nearby urban facilities, and those results are bound to be reflected to real estate costs quite immediately. However, there have been frequently recurring questions regarding objectivity of evaluations in terms of results and methods reflected on indexes such as land costs for various reasons. RPMS -Residence Performance Management System- which targets currently in most cases on urban residential areas, suggests instrumental methodology of objective approach toward sensitive urban residence performance evaluation. This paper explains and suggests instrumental utilization of RPMS and its implementations, evaluation methodology and quantitative way of evaluation. In terms of implementation we explain issues such as adding target locations into new residence planning sites, quantification of properties on evaluation indexes of residential performance and/or habitability in terms of checklists, formulas for evaluation, delicate adjustment of evaluation results by setting weights on evaluation indexes, as well as reports on results. Research on appropriate weights and weight settings regarding evaluation indexes, however, exceeds the range of this paper so that this paper focuses on explaining residence performance evaluation and management methodology.

A Comparison of Human Performance between Operators of a Main Control Room in the SMR

  • Heo, Eun Mee;Byun, Seong Nam;Park, Hong Joon;Park, Geun Ok
    • Journal of the Ergonomics Society of Korea
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    • v.33 no.1
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    • pp.27-37
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    • 2014
  • Objective: This study aims to improve human performance by analyzing the operators' tasks and providing input data on the composition of future SMART operators. Background: SMART is a nuclear reactor for export which needs operators who can satisfy both safety and economic feasibility. Therefore, this study is fundamental research on the composition of operators and this research analyzed SMART tasks in terms of human safety performance. Method: After analyzing 10 SMART EOG in hierarchical task analysis, this study classified task performance types according to task requirements of NUREG-0711 (Rev.3). Results: This study found the task frequency of SMART EOG and 12 operating task types. Conclusion: This study expects that human performance can be improved by analyzing the personal errors, which have the highest task frequency among 12 operating task types. Application: The results of this study can be applied as base data when licensing needs to be acquired.

Proactive Maintenance Framework of Manufacturing Equipment through Performance-based Reliability

  • Kim, Yon-Soo;Chung, Young-Bae
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.22 no.53
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    • pp.45-54
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    • 1999
  • Manufacturing today is becoming increasingly competitive. If a company is to exist and successfully compete, it must pay very careful attention to production management, total quality assurance and total proactive maintenance issues. Overall machine performance, repair efficiency, system level utilization, productivity and quality of output need to be optimized as possible. To accomplish that objective, the behavior of manufacturing equipment and systems need to be monitored and measured continuously if it is possible. Then early warning of possible failure should be generated and proacted on that type of the situation to improve overall operation performance of manufacturing environment. In this paper, Proactive maintenance framework using performance-based reliability structure as enabler technology is proposed. Its paradigm enables one to maximize system through-put and product quality as well as resources in the performance domain. In the case of inadequate knowledge of the failure mechanics, this empirical modeling concept along with performance degradation knowledge can serve as an important product and process improvement tool. The real-time framework extension to proposed framework uses on-line performance information and is capable of projecting the remaining useful period.

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An Experimental Study of Optimal Performance of Rear Wheel Steering Vehicle for Maneuverability (기동성을 위한 후륜 조향 차량의 최적 성능에 대한 연구)

  • Ann, Kookjin;Joa, Eunhyek;Park, Kwanwoo;Yoon, Youngsik;Yi, Kyongsu
    • Journal of Auto-vehicle Safety Association
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    • v.11 no.2
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    • pp.23-28
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    • 2019
  • This paper presents an optimal performance of rear wheel steering vehicle for maneuverability. The maneuverability of vehicle is evaluated in terms of yaw rate, body slip angle and driver input. The maneuverability of vehicle can be improved by rear wheel steering system. To obtain optimal performance of rear wheel steering vehicle, the optimal control history is designed. The high dimensional trajectory optimization problem is solved by formulating a quadratic program considering rear wheel steer input. To evaluate handling performance 7 degree-of-freedom vehicle model with actuation sub-models is designed. A step steer test is conducted to evaluate rear wheel steering vehicle. A response time, a TB factor, overshoot, and yaw rate gain are investigated through objective criteria, assessment webs. The handling performance of vehicle is evaluated via computer simulations. It has been shown from simulation studies that optimal controlled rear wheel steering vehicle provides improved performance compared to others.

An Investigation of Family Entrepreneurship in Ownership and Firm Performance: Empirical Evidence from Pakistan

  • KHAN, Muddasir Riaz;TARIQ, Yasir Bin
    • The Journal of Asian Finance, Economics and Business
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    • v.9 no.5
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    • pp.63-73
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    • 2022
  • In today's financial economics literature, the impact of innovative family ownership and management on firm performance is a prominent concern. In this study, the existence of family firms in the listed sector of Pakistan's economy is investigated. The objective of this study is to examine the performance-oriented relationship of family ownership and active involvement of family member at the CEO position. The theoretical perspectives that underpin this research are agency and stewardship. This analysis used a sample of 315 publicly traded companies from 2009 to 2019. The study's primary independent variables include family influence on ownership and family CEO. Financial performance is the dependent variable that is divided into accounting and market measures. The proxy for accounting measure is return on asset and proxy for market measure is Tobin's Q. This study employs univariate and balanced panel data analysis. For robustness of the analysis random-effects GLS regression is carried out. The empirical results show that that Family Firms outperform Non-Family Firms both in terms of accounting and market measures. In the later part family CEOs firms outperform the firms that have either insider or outsider non-family CEOs. This superior performance is subjected to the positive and statistically significant association between family ownership, management, and financial performance.

Born Global Strategies and the Corporate Performance of Korean Firms

  • Che-Yung Kang;Min-Ho Kim
    • Journal of Korea Trade
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    • v.27 no.1
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    • pp.159-175
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    • 2023
  • Purpose - This paper empirically investigates the relationship between born global strategy and the accounting- and market- based financial performance of Korean firms. Further, this study identifies the characteristics of born global firms (BGs) in comparison with non-BG counterparts in terms of size, R&D, and liability. Design/methodology - Using a database of listed Korean SMEs in the manufacturing sector from 2010 to 2020, this study applies panel generalized least squares (GLS) estimation and logistic regression techniques. Findings - This study finds that BG strategy is negatively related to the firm's accounting-based financial performance, while it is positively related to the market-based financial performance. This study also finds that BGs have higher sales volume and more total assets compared to their non-BG counterparts. In addition, Korean BGs spend more on R&D, and at the same time have higher liability. Originality/value - BGs, by definition, are firms that are actively penetrating foreign markets from the early stages of their establishment. Previous studies of Korean BGs have tried to identify the determinants of BGs' rapid internationalization and their superior performance. However, most of these studies have utilized either qualitative case- or survey-based analyses with relatively limited numbers of observations. From a different perspective, this study provides more objective evidence by investigating how the BG strategy affects the financial and market performance of firms, and by characterizing BGs in terms of financial data.

Entrepreneurial Orientation and Performance for Subcontracting Korean SMEs: The Role of Buyer-Supplier Relationship

  • Youngwoo LEE
    • The Journal of Industrial Distribution & Business
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    • v.14 no.8
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    • pp.27-35
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    • 2023
  • The main objective of this study is to examine the impact of entrepreneurial orientation (EO) on small and medium-sized enterprises' (SMEs) performance in the context of subcontracting buyer-supplier relation. Specifically, we seek to examine whether the power dynamics between buyer and supplier either support or hamper subcontracting SMEs' ability to effectively pursue EO for enhancing their performance. Research design, data, and methodology: We collected survey questionnaires from Korean SMEs that are certified with Inno-biz by the Korean Ministry of SMEs and Startups. The collected data was analyzed using SPSS 26 and AMOS to create an integrated model. Result: Based on the analysis, our findings indicate that the proactiveness and innovativeness dimensions of EO have a positive effect on the SMEs' performance. However, the risk-taking dimension of EO has a negative effect on performance. Additionally, buyer dependency exhibit both positive and negative moderating effects on different dimensions of EO. Conclusion: For SMEs that rely heavily on a particular buyer in terms of sale, pursuing innovativeness dimension of EO could lead to positive performance, while pursuing proactiveness dimension of EO had a negative moderating effect on performance.

Comprehensive System Framework for Visual Fatigue and Cognitive Performance Management based on Predictive Models

  • Dahyun JUNG;Hakpyeong KIM;Seunghoon JUNG;Hyuna KANG;Seungkeun YEOM;Juui KIM;Taehoon HONG
    • International conference on construction engineering and project management
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    • 2024.07a
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    • pp.988-995
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    • 2024
  • With the modern workplace's increasing dependence on computer-based tasks, traditional lighting standards have been identified as insufficient for optimal occupant comfort and productivity. Therefore, this paper presents a comprehensive system framework designed to manage visual fatigue and cognitive performance within office environments. Classification and regression models using gradient boosting machine and random forest to predict visual fatigue and cognitive performance were developed based on data collected from 16 subjects in experiments. To this end, the proposed system consists of two modules: the first module predicts visual fatigue and cognitive performance levels using classification models, offering immediate feedback to occupants. The second module, targeted at facility managers, uses regression models and a genetic algorithm to identify optimal lighting settings, aiming to minimize visual fatigue and enhance cognitive performance. This system can help to manage visual fatigue and cognitive performance simultaneously, contributing to improvement of eye health and productivity.

Comparison of Objective Metrics and 3D Evaluation Using Upsampled Depth Map (깊이맵 업샘플링을 이용한 객관적 메트릭과 3D 평가의 비교)

  • Mahmoudpour, Saeed;Choi, Changyeol;Kim, Manbae
    • Journal of Broadcast Engineering
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    • v.20 no.2
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    • pp.204-214
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    • 2015
  • Depth map upsampling is an approach to increase the spatial resolution of depth maps obtained from a depth camera. Depth map quality is closely related to 3D perception of stereoscopic image, multi-view image and holography. In general, the performance of upsampled depth map is evaluated by PSNR (Peak Signal to Noise Ratio). On the other hand, time-consuming 3D subjective tests requiring human subjects are carried out for examining the 3D perception as well as visual fatigue for 3D contents. Therefore, if an objective metric is closely correlated with a subjective test, the latter can be replaced by the objective metric. For this, this paper proposes a best metric by investigating the relationship between diverse objective metrics and 3D subjective tests. Diverse reference and no-reference metrics are adopted to evaluate the performance of upsampled depth maps. The subjective test is performed based on DSCQS test. From the utilization and analysis of three kinds of correlations, we validated that SSIM and Edge-PSNR can replace the subjective test.