• Journal of Korea Society of Industrial Information Systems
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• v.22 no.2
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• pp.15-25
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• 2017

A System can be more Dependable from some types of Threats if the Dependability Level Against the Threat on the System is Increased. However, The Dependability-performance Tradeoff should be Considered because the Increased Dependability may Degrade the Performance of the System. Therefore, it is Efficient to Temporally Increase the Dependability Level to High only when an Threat is Predicted on the System in a Short time while Maintaining the Level in Low or mid in Normal Situations. In this Paper, we Present a Threat Prevention Strategy for a Networked Node by Dynamically Changing the Dependability Level According to the Threat Situation on its Logically/physically Neighboring Nodes. As case Studies, we Employ our Strategy to an Internet Server Against TCP SYN Flood Attacks and to a Checkpoint and Rollback System Against Transient Faults. Our Performance Analysis Shows that our Strategy can Effectively Relieve the Damage of the Failure without Serious Performance Degradation.

• Journal of Power Electronics
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• v.16 no.6
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• pp.2162-2172
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• 2016

This paper presents a Direct Torque Control (DTC) strategy for the five-phase induction motor driven by a three-level five-phase inverter in order to improve the performance of the five-phase induction motor. In the proposed DTC technique, only 22 voltage vectors out of 243 available voltage vectors in a three-level five-phase inverter are selected and are divided in 10 sectors each with a width of $36^{\circ}$. The four different DTC combinations (DTC-I, II, III and IV) for a three-level five-phase induction motor drive are investigated for improving the performance of five-phase induction motor. All four of the DTC strategies utilize a combination of the same large and zero voltage vectors, but with different medium voltage vectors. Out of these four techniques, DTC-II gives the best performance when compared to the others. This DTC-II technique is analyzed in detail for improvements in the performance of five-phase induction motor in terms of torque ripple, x-y stator flux and Total Harmonics Distortion (THD) of the stator phase current when compared to its two-level counterparts. To verify the effectiveness of the proposed three-level five-phase DTC control strategy, a DSP based experimental system is build. Simulation and experimental results are provided in order to validate the proposed DTC technique.

• Management & Information Systems Review
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• v.21
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• pp.271-297
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• 2007

Since B2C EC websites not only become a valuable channel for selling goods to customers and for communicating with the potential clients, but also offer companies an important vehicle for attaining competitive advantages in the new digital economy, the design and content of website must reflect its business goals and customers' needs. However, as little empirical evidence on the effect of B2C EC website contribution of firm performance exist, the functionality of B2C EC website has been decided voluntarily from its business experience. Hence, there has been a call for a rigorous empirical studies to examine the function level of an B2C EC website application. The purpose of this study is to examine the relationship between the function level of B2C EC website and its performance considering the characteristics of B2C EC strategy as moderating variable. 125 questionnaires from internet shopping malls which sell physical goods direct to an individual end consumer were collected. The results showed that four factors(price, product recognition, reliability enhancement, and purchase confidence) affect positive effects on the performance of shopping mall, and the characteristics of B2C EC strategy can be considered as a significant moderating variable between price factor and the performance of shopping mall.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.11 no.3
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• pp.177-187
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• 2016

The purpose of this study is to look into the influence of salesperson's human networking and knowledge on its job in an insurance company in its performances and to suggest how to effectively manage and develop salespersons. For this study, 305 salespersons participated in a questionnaire survey and we used T-TEST to analyze the data. The results are as follows. Its performance is positively influenced by salesperson's networking and knowledge on its job. In term of moderating effect on the attitude for its job, making efforts to organize networking was rejected, however the attitude for retaining their networking positively affected to the performance. As a result, the higher the level of salesperson's knowledge and networking is the higher its performance. To increase competitiveness, an insurance company has a strategy for the support to organize networking and the training of salespersons to become high performers.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.35
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• pp.25-38
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• 1995

The purpose of this study identificate the sources of stress, and then find the influenced factor on the performance of organization by thoses. The sources of stress be limited on the level of individuals and the results of its also be did on the level of organization. The finding of the study will contribute to the effective management of stress by the manager in organization. As a results, rational management would made the quality of life of members of organization to level up, and the goals of organization to achieve rationally.

• Journal of Distribution Science
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• v.13 no.8
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• pp.15-25
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• 2015

Purpose - There is a lack of research on how much corporate control is sufficient for effective subsidiary business-related decision making. To address this research gap, this study analyzes the impact of the level of control of a Korean corporation's headquarters on its overseas subsidiary performance. Research design, data, methodology - The study's sample comes from the Overseas Korean Business Directory of KOTRA. A multiple regression analysis empirically confirmed the relationship between the headquarters level of control over the subsidiaries and their performance. Results - The results show that the greater an organization's headquarters control over strategic issues, the greater the subsidiary's non-financial performance. However, quick decision-making through decentralization promotes the rapid selection of successful new products that can provide a competitive advantage. Conclusion - This study shows that the impact of control levels on subsidiary performance depends on the type of control involved. Specifically, while low levels of control over operational issues had a positive (+) influence on subsidiary non-financial performance, high control levels led to improved non-financial performance with regard to strategic issues among the subsidiaries.

• Journal of the Korean Society of Safety
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• v.18 no.2
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• pp.73-78
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• 2003

In order to improve the safety performance oi construction projects, effective and corporative safety management program between head office and job site must be implemented. And its performance must be measured and analyzed for the identification of the problems in the safety management area. This study proposes a previous evaluation model of safety performance for the large construction firm in order to enhance their safety level. The fundamental data for proposed model is based on the past research(Son 2002), which is structured of evaluation criteria. weighted factor. statistical evaluation formula. The model would help the firm management in identifying the weak areas of safety performance in terms of the degree performing certain safety tasks. It is expected that the model could contribute to achieving the "zero accident" level.ot; level.

• Earthquakes and Structures
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• v.15 no.6
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• pp.639-654
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• 2018

Rocking motion have been used for achieving the 'resilient buildings' against earthquakes in recent studies. Low-rise buildings, unlike the tall ones, because of their small aspect ratio tend to slide rather than move in rocking mode. However, since rocking is more effective in seismic response reduction than sliding, it is desired to create rocking motion in low-rise buildings too. One way for this purpose is making the building's structure rock on its internal bay(s) by reducing the number of bays at the lower part of the building's skeleton, giving it a mushroom form. In this study 'mushroom skeleton' has been used for creating multi-story rocking regular steel buildings with square plan to rock on its one-by-one bay central lowest story. To show if this idea is effective, a set of mushroom buildings have been considered, and their seismic responses have been compared with those of their conventional counterparts, designed based on a conventional code. Also, a set of similar buildings with skeleton stronger than code requirement, to have immediate occupancy (IO) performance level, have been considered for comparison. Seismic responses, obtained by nonlinear time history analyses, using scaled three-dimensional accelerograms of selected earthquakes, show that by using appropriate 'mushroom skeleton' the seismic performance of buildings is upgraded to mostly IO level, while all of the conventional buildings experience collapse prevention (CP) level or beyond. The strong-skeleton buildings mostly present IO performance level as well, however, their base shear and absolute acceleration responses are much higher than the mushroom buildings.

• Korean Journal of Computational Design and Engineering
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• v.21 no.2
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• pp.99-110
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• 2016

The quality of building space program is a key to measure how the building performance satisfies its owner and users. However assuring its efficiency requires reliable criteria that reflect high level experience knowledge in the field. This study suggests a plan to gauge the level of building space performance using expert knowledge, which has not been utilized well enough but should play a critical role. In order to setup an expert system measuring level of the space program, we firstly optimized the space areas to the best case in a knowledgebase and use them as criteria to judge the quality of the spaces extracted from BIM model. We found the experimental results show us a promising way of measuring a relative quality of the space programs.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.6
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• pp.35-48
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• 1993

In this paper, a hierarchical motion vector estimation algorithm using pyramidal structure is proposed. Using a smaller measurement window at each level of a pyramid than that of the conventional scheme, the proposed algorithm, based on the TSS(three step search), reduces the computational complexity greatly with its performance comparable to that of the TSS. By increasing the number of cnadidate motion vectors which are to be used as the initial search points for motion vector estimation at the next level, the performance improves further. Then the computational complexity of the proposed hierarchical algorithm depends on the number of candidate motion vectors, with its PSNR (peak signal to noise ratio) ranging between those of the TSS and the full search method. The simulation results with two different block sizes and various test sequences are given and its hardware implementation is also sketched.