• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.212-214
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• 2020

리튬이온 배터리를 고온의 환경에서 장시간 운용함에 따라 배터리 내부 물질의 변형 및 특성 변화가 발생하여 안전성의 문제가 발생하게 된다. 배터리의 안전성을 향상하기 위해 배터리의 고장 및 이상 상태를 진단 및 탐지하는 기법들의 연구가 진행되고 있다. 본 논문에서는 배터리의 이상 상황을 모사하기 위해 열폭주의 한 가지 방법인 고온의 환경에서 배터리의 특성 변화를 전기화학적 임피던스 분광법을 통해 분석하였으며, 등가회로 모델의 특성 인자를 활용하여 이상 상황을 탐지할 수 있는 이동 평균 추세선 기반의 이상 탐지 기법을 제안하며, 열폭주가 발생한 데이터를 통해 이상 탐지 기법을 검증한다.

• Journal of the Korean Geotechnical Society
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• v.21 no.4
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• pp.155-165
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• 2005

Love wave and Rayleigh wave are the major elastic waves belonging to the category of the surface wave. Those waves are used to determine the ground stiffness profile using their dispersion characteristics. The fact that Love wave is not contaminated by P-wave makes Love wave superior to Rayleigh wave and other body waves. Therefore, the information that Love wave carries is more distinct and clearer than that of others. Based on theoretical research, the joint inversion analysis that uses the dispersion information of both Love and Rayleigh wave was proposed. Numerical analysis, theoretical model test, and field test were performed to verify the joint inversion analysis. Results from 2D, 3D finite element analysis were compared with those from the transfer matrix method in the numerical analysis. On the other hand, the difference of results from each inversion analysis was investigated in the theoretical model analysis. Finally, practical applicability of the joint inversion analysis was verified by performing field test. As a result, it is confirmed that considering dispersion information of each wave simultaneously prevents excessive divergence and improves accuracy.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.1
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• pp.1-10
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• 2013

In this study, impact vibration tests are applied to analyze the vibration characteristics of caisson-type breakwater, and the results obtained from vibration tests are compared with numerical simulation results considering fluid-soil-structure interaction effects to verify the feasibility of a numerical analysis model. It is found that natural frequencies are reduced as amount of 1.7-4.3% after additional parapet structure is added to increase the height of breakwater, and the same results was observed from the numerical simulation study. Through the comparison, it was verified that the vibration tests and numerical simulation study can be applied to evaluate the vibration characteristics of caisson-type breakwater.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.12
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• pp.1485-1492
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• 1999

대규모 시스템 명세의 올바름을 검증하기 위한 유한 상태 LTS에 기반을 둔 CTL논리 적용에 있어 가장 큰 문제점은, 시스템 내부의 병렬 프로세스간의 상호작용으로 인한 상태폭발이다. 그러나 Modal mu-calculus 논리를 시스템 안전성 및 필연성 특성 명세에 사용하면, 행위에 의한 순환적 정의가 가능하므로 상태폭발 문제가 해결 가능하다. 본 논문에서는 LTS로 명세화된 통신 프로토콜 시스템 모델의 안전성 및 필연성 특성을 모형 검사 기법에 의해 검증함에 있어, 시제 논리로 사용된 Modal mu-calculus 안전성 및 필연성 논리식과 CTL 의 안전성 및 필연성 논리식의 극한값이 동일함을 두 논리식을 만족하는 상태 집합이 같다는 것을 보임으로써 증명한다. 증명된 결과는 I/O FSM 모델로 표현된 통신 프로토콜의 안전성 및 필연성 검사를 위해 이론적인 기반으로서, 컴퓨터를 이용한 모형검사 기법에 효과적인 방법으로 응용이 가능하다.Abstract In applying CTL-based model checking approach to correctness verification of large state transition system specifications, the major obstacle is the combinational explosion of the state space arising due to interaction of many loosely coupled parallel processes. If, however, the modal mu-calculus viewed as a CTL-based logic with recursion, is used to specify the safety and liveness property of a given system, it is possible to resolve this problem. In this paper, we discuss the problem of verifying communication protocol system specified in LTS, and prove that a logic expression specifying safety and liveness in modal mu-calculus is semantically identical to the maximum value of the expression in CTL. This relation is verified by the proof that the sets of states satisfying the two logic expressions are equivalent. The proof can be used as a theoretical basis for verifying safety and liveness of communication protocols represented as I/O FSM model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.302-310
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• 2018

This study was conducted to develop a unified structural model that defines relationships among factors that affect Multi Cultural Acceptance (MCA) for adolescents. This study was performed using the dataset from the 2016 Korean Children and Youth Panel Survey (KCPS). We analyzed the survey result from the dataset at the 0.05 significance level using the SPSS and AMOS version 22 programs. Specifically, we investigated several demographic characteristics of the survey participants by a descriptive analysis method that adopted the maximum likelihood estimate method to verify the fitness of the hypothetical model and the hypotheses therein. In addition, we applied the ${\chi}^2$-test, GFI, AGFI, CFI, IFI, and RMSEA to show the fitness level of our structural model. The results showed that our proposed structural model demonstrated a fine fitness level. We found that key factors that affect MCA for adolescents were ego-resilience, peer relationships, and sense of community. Overall, the results of our study indicate that combinational intervention is needed to help adolescents lift their ego-resilience, as well as to develop peer relationships and a sense of community.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.4 s.109
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• pp.319-328
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• 2006

This paper presents a method for analysis of the mechanical behavior of a crankshaft in a four-cylinder internal combustion engine. The purpose of the analysis was to study the characteristics of the shaft in which the pin and arm parts were assumed to have a uniform section in order to simplify the modal analysis. The results of natural frequency transfer function and mode shape were compared with those obtained by experimental work. The results obtained from the comparison showed a good agreement with each other and consequently verified the analysis model. Furthermore, a prediction of crankshaft characteristics under the firing condition, by using the model, was performed. This study describes a new method for analyzing the dynamic behavior of crankshaft vibrations in the frequency domain based on the initial firing stages. The new method used RMS values to calculate the energy at each bearing journal and counter weight shape modification under the operating conditions.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.6
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• pp.29-37
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• 2016

This paper proposes a shape optimization of the metal boss for a composite motor case using finite element analysis. For the structural safety and the weight reduction of the composite motor case, under the internal pressure, the fiber stress in the dome area and the tightening bolt stress are constrained and the boss weight is set to objective function, respectively. The response surface models are constructed for the performance characteristics by using response surface method. The significance of the design variables about the performance characteristics is evaluated through the ANOVA(analysis of variance) and the goodness of fit test for the constructed model is performed through the regression analysis. The SQP(sequential quadratic programming) algorithm is used for the optimization and the proposed method is verified by performing structural analysis for the optimum shape.

• The Journal of the Korea Contents Association
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• v.13 no.4
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• pp.361-375
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• 2013

While the mobile application market is growing fast, the revenues of the majority apps are declining. Moreover, paid mobile application prices and purchases have been slow because of intensifying competition. However, the conventional studies focused only on the acceptance factor of mobile applications, so they cannot explain the phenomenon such as acceptance resistance for paid mobile applications. Therefore, our study tries to analyze the factors for the acceptance resistance of users for paid mobile applications. The research model in this paper, which is based on S-O-R model, verified through surveys how social influence and app characteristics affect user perception and how user perception affects to app resistance. The results of our study showed that paid mobile applications happened to be destroyed in front of the chasm because of the perceived loss. Consequently, the results implicate that the developers should lower the initial price and actively react to the negative reviews in order to lower the perceived loss. Moreover, the results verified that a sense of self-efficacy can lower application acceptance resistance by including personal properties to our research model as control variables.

• The Journal of the Korea Contents Association
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• v.17 no.5
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• pp.440-448
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• 2017

This study aims to determine the factors affecting people's intention to use mobile delivery application services. The technology acceptance model (TAM) was employed and a survey was conducted on 300 delivery application users. As a result, personal innovativeness was found to have a positive effect on perceived ease of use and perceived playfulness. Self-efficacy turned out to have a positive influence on perceived ease of use and perceived playfulness. Next, perceived ease of use was found to positively affect both perceived usefulness and perceived playfulness, and perceived usefulness and playfulness had a positive effect on the intention to use the service as well. Lastly, personal innovativeness and self-efficacy were found to have a significant indirect influence on the intention to use the service. This study suggests users can be induced to voluntarily and continuously use the service, if their personal characteristics and perception of the service are considered in the future development of the service.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.3
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• pp.191-196
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• 2022

In this study, the anisotropic mechanical property of fused deposition modeling three-dimensional (3D) printing based on lamination direction was verified by a tensile test. Moreover, the property was applied to solid isotropic materials with penalization-based topology optimization. The case of the lower control arm, one of the automotive suspension components, was considered as a benchmark problem. The optimal topological results varied depending on the external load and anisotropic property. Based on these results, two test specimens were fabricated by varying the lamination direction of 3D printing; a tensile test utilizing 3D non-contact strain gauge was also conducted. The measured strain was compared with that obtained by computer-aided engineering response analysis. Quantitatively, the measurement and analysis results are found to have good agreement. The effectiveness of topology optimization considering the lamination direction of 3D printing was confirmed by the experimental result.