• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.184-187
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• 2005

Physical changes in a structural system may cause changes in mechanical impedance of the system. Due to the electro-mechanical coupling effect in piezoelectric materials, this change can be monitoring by the electrical impedance of the piezoelectric sensor. In this paper, the variability of electro-mechanical impedance caused by temperature effect is assessed to adjust impedance data used for EMI based damage detection in beams. First experiments on beams are described. Next, experiments were performed under the temperature varying condition, in the range of $3^{\circ}C\;to\;23^{\circ}C$. Finally, the relationship between temperatures and impedance signatures is analyzed empirically temperature-frequency patten for the test structure.

• 대한조선학회논문집
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• 제58권2호
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• pp.97-104
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• 2021

Together with the emerging of the Eco-ship, the application of large-diameter and high-efficiency propeller required more careful attention than before in the design of the shafting system. After the adoption of Environmentally Acceptable Lubricants (EAL) to the stern tube lubrication oil, a number of aft stern tube bearing accidents have been reported, and a variety of institutions have actively conducted research on the cause relationship. This study attempted to find the cause of the accident by measuring the alignment of the shafting system of a medium-sized product/chemical tanker with aft stern tube bearing damage and analyzing the reaction force of each bearing. In addition, a reasonable solution to the correction of the shaft alignment was suggested and the feasibility was reviewed. Through various measured data and analysis, the actual installation of shafting system was slightly different from the design drawing condition, but it was found that each bearing load distribution was within the allowable range. Therefore, it was confirmed that the cause of this accident was due to the dissatisfaction the misalignment slope of aft stern tube bearing rather than the effect of the bearing overload. As a solution to this cause, countermeasures such as double slope were suggested in the aft stern tube bearing, and the characteristics of EAL also seem to have an indirect effect.

• Journal of Information Technology Applications and Management
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• 제28권3호
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• pp.31-48
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• 2021

Knowledge is a key resource for organizations to gain and maintain competitive advantage. Therefore, it is important for organizations to motivate employees to share knowledge with each other in order to achieve optimal performance of knowledge resources. Despite the efforts of organizations to share knowledge, knowledge hiding is still prevalent among employees. In this paper, we want to analyze the factors that may cause more general and pervasive knowledge-hiding behavior in organizations through empirical analysis. The results of this study show that, first, the relationship between team cohesion and knowledge hiding has been verified differently depending on the sub-behavior of knowledge hiding : playing dumb, evasive hiding, and rationalized hiding. Team cohesion has been shown to significantly reduce the playing dumb and evasive hiding. On the other hand, it was shown that team cohesion did not have a significant causal relationship with rationalized hiding. Second, the moderating effect of ethical leadership has been statistically significant in terms of team cohesion and relationships with playing dumb and evasive hiding. In other words, the higher the ethical leadership, the stronger the negative relationship between team cohesion and knowledge hiding. Finally, the theoretical and practical implications of this paper and future research directions are discussed.

• 대한안전경영과학회지
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• 제17권4호
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• pp.381-396
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• 2015

The study proposes multiple TRIZ contradiction solution strategies for addressing PC (Physical Contradiction) and TC (Technical Contradiction) by implementing TRIZ cause-and-effect tree. The problem associated with TC of the ends is solved by PC of means which employs a causal relationship between causes and effects. The TRIZ contradiction solution strategies demonstrated in this research are classified into 3 types of combined strategy as follows: 1. To-Be PC and AS-Is PC, 2.To-Be PC and As-Is TC, 3.As-Is PC and To-Be TC. The combined strategy of To-Be PC and As-Is PC is similar to a divide-and-conquer technique. This strategy adopts parallel strategies using 4 separation principles in time, in space, between parts and the whole, and upon condition of two reversed-PCs. Moreover, its application elucidates the conflict relationship of two TCs from the study. The integrated 4 separation principles and 40 inventive principles present an effective synergy effect from the combination, and further addresses the problems in the TRIZ contradiction resolution strategies. Combined strategy of To-Be PC and As-Is TC implements the 40 inventive principles that To-Be PC of the means resolves the As-Is TC of the ends. Combined strategy of As-Is PC and To-Be TC also uses inventive principles to the As-Is PC of the means to solve the To-Be TC of the ends. In addition, propositional and logical relationship of necessary and sufficient conditions between TC and PC is used to support the validity of 3 TRIZ contradiction solution strategies. In addition, 3 other strategies of necessary and sufficient conditions validate the contraposition relationship of the truth table. This study discusses TRIZ case studies from National Quality Circle Contest from the years between 2011 and 2014 to provide the usage guidelines of TRIZ contradiction solutions for quality purposes. Examining analysis from the case studies and investigating combined strategies allows the users to obtain comprehensive understanding.

• 문화기술의 융합
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• 제3권4호
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• pp.137-144
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• 2017

본 연구의 목적은 패션기업의 SCM(Supply Chain Management) 환경에서 B2B 관계 구축에 영향을 미치는 CRM(Customer Relationshio Management)요소들을 밝히는 것이다. 특히 이러한 CRM 요소들이 기업간 권력구조와 관계없이 비즈니스의 모든 영역에서 유의한 효과가 있는지 탐색적으로 살펴보고자 한다. 이를 위해 질적연구방법과 양적연구방법을 병행한 통합적 접근법을 이용하여 탐색적 연구가 진행되었다. 패션기업에 근무하는 전문가 5명을 대상으로 하여 심층면접을 실시하였으며 이를 통해 연구모형을 구성하였다. 그리고 설문지를 통하여 이러한 모델을 실증적으로 검증하기 위한 양적연구를 진행하였다. 그 결과 첫째, 패션기업 간 거래유형에 따라 장기지향적 관계/충성도, 전환 비용에 영향을 미치는 CRM의 모형이 구성되었다. 둘째, 구성된 연구모형을 양적으로 검증한 결과 변수 간 인과관계는 부분적으로 지지되었다. 구체적으로 기업간 관계구축에 가장 큰 영향을 미치는 CRM요인은 매출보장과 특별할인이었다. 또한 고객화된 제품과 품질, 편의성, 경쟁력 있는 가격, 제품/시스템/서비스 개발과 같은 요소들이 관계 구축 및 전환비용 상승에 영향을 미칠 것으로 나타났다.

• 수면정신생리
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• 제9권1호
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• pp.5-8
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• 2002

Stroke is a leading cause of death in most developed countries and some developing countries including South Korea. It is well known that stroke has is related in some way with several sleep disorders. At first, the onset time of stroke varies according to circadian rhythm. Early morning is the most prevalent time and late evening the least. The changes of blood pressure, catecholamine level, plasminogen activity and aggregation of platelet during sleep have been suggested as possible mechanisms. Sleep apnea (SA), a representative disorder in the field of sleep medicine, is found in more than 70% of acute stroke patients compared to 2-5% of the general population. Various sleep related breathing disorders occur after stroke and snoring is a distinct risk factor for stroke. So the relationship between stroke and SA is obvious, but the cause and effect are still not clearly known. Also, stroke may cause many sleep related problems such as insomnia, hypersomnia, parasomnia and changes in sleep architecture. Patients, family members and even medical personnel often ignore stroke-related sleep problems, being concerned only about the stroke itself. The clinical impacts of sleep problems in stroke patients may be significant not only in terms of quality of life but also as a risk factor or prognostic factor for stroke. More attention should be paid to the sleep problems of stroke patients.

• Journal of Information Technology Applications and Management
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• 제23권3호
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• pp.71-86
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• 2016

This paper proposes a new software quality model composed of a hierarchy of software quality views and three software quality characteristics models. The software view hierarchy is composed of two levels : end view and means view at the first level, contingency view and intrinsic view as sub-views of means view. Three software quality characteristics models are activity quality characteristics model, contingency quality characteristics model, and intrinsic quality characteristics model, which correspond to end view, contingency view, and intrinsic view respectively. This paper also reclassifies characteristics of ISO/IEC 25000 series SQuaRE's software product quality model according to the proposed software quality model. The results illustrate clearly the shortcomings of SQuaRE's product quality model and how to overcome them. First of all, most of SQuaRE's product characteristics should be redefined and conceptually clarified according to the views on which they are really rested. Much more characteristics should be supplemented too. After that, rigorous empirical researches will become relevant. Causal relationships between activity quality characteristics and characteristics of means view should be empirically researched.

• Structural Engineering and Mechanics
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• 제39권3호
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• pp.303-316
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• 2011

Experimental tests have shown that glass exhibits very different strengths when tested under biaxial and uniaxial conditions. This paper presents a study on the effects of biaxial stresses on the notional ultimate strength of glass. The study involved applying the theory of elasticity and finite element analysis of the Griffith flaw in the micro scale. The strain intensity at the tip of the critical flaw is used as the main criterion for defining the limit state of fracture in glass. A simple and robust relationship between the maximum principal stress and the uniaxial stress to cause failure of the same glass specimen has been developed. The relationship has been used for evaluating the strength values of both new and old annealed glass panels. The characteristic strength values determined in accordance with the test results based on 5% of exceedance are compared with provisions in the ASTM standard.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.302-307
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• 2004

The major flow-induced vibration mechanisms such as fluid-elastic and turbulence excitation can cause the various types of wear of the steam generator tubes in unclear power plant. It is generally accepted that the tube wear due to vibration is affected by the presence of gap clearance between tube and support plate. Connors showed that the tube wear depth could be estimated by using the relationship between wear volume and sliding distance for contact time. Au-Yang predicted the wear depth by using the nonlinear characteristics of normal work rate to contact time. In this study the effect of gap size on the steam generator tubes wear is analyzed by deriving the wear depth versus normal work rate relationship from these previous results.

• 품질경영학회지
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• 제38권4호
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• pp.512-520
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• 2010

This research is the analysis of using structural equation method in order to investigate the cause and effect relationship among the elements related to the innovation activity and the degree of the influence on that, and in order to make sure the sequential processes into the meaningful management performance for improving the efficiency and effectiveness of a various of innovation activities performing in the domestic small and medium enterprise. To perform this research, we surveyed CEOs, managers, workers working for manufacturing business, we distributed 250 sheets totally and withdrew 206 sheets. we analyzed 169 sheets that we could use for this research using SPSS 15.0 and AMOS 18.0 program.