• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.2
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• pp.23-31
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• 2018

In recent years, as the development of construction technology and population increase, buildings are becoming more complex and high-rise. These large scale buildings are difficult to secure fire and evacuation safety when fire occurs. So it is necessary to prepare specific measures. According to this situation, in 2011, Republic of Korea officially launched Performance-based Design in "Fire-fighting system Installation business Act". But even 6 years passed since the enforcement, there are still faces manifold problems in the course of implementation. In order to examine the necessary improvements, in this study, I conducted interviews and questionnaires with experts, investigated the improvement items under current laws. And draw up a measures for that items. The subjects of the survey were fire-fighting officer, professional engineer fire fighting, fire protection planner and professor in Daegu. As a result of twice surveys, a total of 19 items are derived. And then compared and analyzed the criteria of overseas countries, and suggested improvement directions for final items. In addition, conducted a third questionnaire survey on the proposed improvement direction to verify the appropriateness of the alternative. The results of this study will be used as basic data to deal with the general problems of performance-based design in future, and further study on each item will be needed.

• Journal of Communications and Networks
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• v.16 no.2
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• pp.193-201
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• 2014

In cognitive radio networks, the packet transmissions of the secondary users (SUs) can be interrupted randomly by the primary users (PUs). That is to say, the PU packets have preemptive priority over the SU packets. In order to enhance the quality of service (QoS) for the SUs, we propose a spectrum access strategy with an ${\alpha}$-Retry policy. A buffer is deployed for the SU packets. An interrupted SU packet will return to the buffer with probability ${\alpha}$ for later retrial, or leave the system with probability (1-${\alpha}$). For mathematical analysis, we build a preemptive priority queue and model the spectrum access strategy with an ${\alpha}$-Retry policy as a two-dimensional discrete-time Markov chain (DTMC).We give the transition probability matrix of the Markov chain and obtain the steady-state distribution. Accordingly, we derive the formulas for the blocked rate, the forced dropping rate, the throughput and the average delay of the SU packets. With numerical results, we show the influence of the retrial probability for the strategy proposed in this paper on different performance measures. Finally, based on the trade-off between different performance measures, we construct a cost function and optimize the retrial probabilities with respect to different system parameters by employing an iterative algorithm.

• Journal of Biosystems Engineering
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• v.11 no.1
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• pp.24-30
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• 1986

In order to collect the engine performance data accurately, rapidly and reliabily, the microcomputer-based engine performance test system was developed and tested. The system measures engine shaft torque and speed, fuel consumption, exhaust gas temperature, engine shaft power and fuel consumption ratio. The system consisted of 32 channels 8 bit A/D converter, time clock, dynamic strain amplifier and signal conditioning circuits to amplify and filter the electrical signal from transducers. Most of transducers were devised for low cost, easy setting and self-manufacturing. The system has been installed on a small kerosene engine (DAEDONG NA50B).

• Journal of the Korean Society of Safety
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• v.35 no.4
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• pp.56-63
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• 2020

The government has established various policies focusing on accident prevention to reduce the accident rate in the construction industry, but the effect is still insignificant. These results allude that there are still many problems in terms of usability. Although construction safety accidents usually have characteristics that occur during construction, the laws and systems should include the pre-construction cycle (plan/order - design - construction business management- construction) to eliminate risk factors in advance. The purpose of this study is to analyze the performance evaluation of the construction safety system before construction rather than during construction. In the pre-construction phase (plan/ order-design-constuction business management), we intend to investigate and analyze measures to prevent safety accidents and identify a system that lacks the ability to implement. Specifically, we analyzed what to focus on as precautionary measures in the planning, ordering, designing, and supervising. To improve them, we made a questionnaire based on the role related to construction safety for each subject, and seek implications for lack of performance through interviews. Based on the results, some ways to improve the safety system were proposed.

• Journal of Korean Institute of Industrial Engineers
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• v.29 no.1
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• pp.100-113
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• 2003

In order to improve business competency by the IS(Information Systems), every enterprise needs to evaluate the current level of IS performance and their utilization. The evaluation that measures the performance of enterprise information systems and diagnoses their effectiveness of business goals and efficiency of resources should represent the useful informations based on sustainable goal-oriented viewpoints to managers. This work develops an integrated evaluation system for continuous maturity of information systems performance, enabling enterprises to achieve their goals of information systems and related business strategies. The integrated evaluation system has been applied to performance measurement of information systems with a huge set of real data from domestic industries for three years, and proven reliable and practical.

• The Korean Journal of Applied Statistics
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• v.28 no.5
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• pp.871-883
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• 2015

Vector autoregressive (VAR) models in high dimension suffer from noisy estimates, unstable predictions and hard interpretation. Consequently, the sparse vector autoregressive (sVAR) model, which forces many small coefficients in VAR to exactly zero, has been suggested and proven effective for the modeling of high dimensional time series data. This paper studies coupling measures to select non-zero coefficients in sVAR. The basic idea based on the simulation study reveals that removing the effect of other variables greatly improves the performance of coupling measures. sVAR model coefficients are asymmetric; therefore, asymmetric coupling measures such as Granger causality improve computational costs. We propose two asymmetric coupling measures, filtered-cross-correlation and filtered-Granger-causality, based on the filtered residuals series. Our proposed coupling measures are proven adequate for heavy-tailed and high order sVAR models in the simulation study.

• Korean Journal of Remote Sensing
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• v.25 no.3
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• pp.263-270
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• 2009

Noise band removal is a crucial step before spectral matching since the noise bands can distort the typical shape of spectral reflectance, leading to degradation on the matching results. This paper proposes a statistical noise band removal method for hyperspectral data using the correlation coefficient between two bands. The correlation coefficient measures the strength and direction of a linear relationship between two random variables. Considering each band of the hyperspectral data as a random variable, the correlation between two signal bands is high; existence of a noisy band will produce a low correlation due to ill-correlativeness and undirected ness. The unsupervised k-nearest neighbor clustering method is implemented in accordance with three well-accepted spectral matching measures, namely ED, SAM and SID in order to evaluate the validation of the proposed method. This paper also proposes a hierarchical scheme of combining those measures. Finally, a separability assessment based on the between-class and the within-class scatter matrices is followed to evaluate the applicability of the proposed noise band removal method. Also, the paper brings out a comparison for spectral matching measures. The experimental results conducted on a 228-band hyperspectral data show that while the SAM measure is rather resistant, the performance of SID measure is more sensitive to noise.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.5
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• pp.1256-1265
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• 1996

Soft-decision detectors are used in many FEC and ARQ schemes to enhance the bit-error-probability and system throughput. Also, the hybrid-ARQ protocol is a very efficient schemeto achieve overall performance improvement. In this paper, we propose a new hybrid-ARQ protocol based on the first-order Reed-Muller codes employing soft-decision detectors. The Reed-Muller codes have the virtue of being able to use the fast Green machine decoder that is simple to implement. As the performance measures, the bit-error-probability and system throughput are evaluted for the proposed hybrid-ARQ procol, and compared with those of other hybrid-ARQ schemes. It is shown that the use of the proposed hybrid-ARQ protocol results in significant performance improvement without causing much loss in view of system complexity.

• Journal of Information Technology Applications and Management
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• v.23 no.2
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• pp.113-141
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• 2016

This study identifies and validates the factors that affect sales performance of salespersons in the business software industry. In the study, in order to measure the dependent variable (performance of the salesperson) more comprehensively, multiple items are utilized and both outcome and behavior indicators are used. Independent variables are identified based on the classification of Verbeke et al. [(2011] including sales related knowledge, degree of adaptiveness, role ambiguity, and work engagement. Results of the hypotheses testing show that 'sales related knowledge' and 'work engagement' are statistically significant factors, but 'degree of adaptiveness' and 'role ambiguity' are not. This study has a few limitations and future research direction to overcome the limitation is suggested : use of both perceptions of the salesperson and objective measures in measuring the related variables; study including cognitive ability; analyses of the factors across various types of software companies; and analyses of the factors on the team level.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.250-258
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• 2019

Due to the problems associated with the aging of industrial complexes, research on the decline of industrial complexes is being conducted. In the case of decline, it is necessary to not respond immediately, but with a crisis, it is necessary to minimize the impact on the industrial complex through preemptive responses to the external environment and internal changes. Therefore, it is necessary to develop a crisis index that can systematically predict and evaluate changes in the industrial complex. In this research, a method for extracting the crisis index of an industrial complex is developed. We derive performance measures for developing the crisis index, deriving the relative importance of performance measures based on the analytical hierarchy process. Because units of performance measurement are different, a normalization method is developed to sensitively reflect change. Based on the relative importance and normalized values of the performance measures, the crisis index of the industrial complex is developed and applied to a national industrial complex in order to verify its applicability.