• Wind and Structures
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• v.17 no.2
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• pp.203-225
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• 2013

An analysis framework for vehicle-bridge dynamic interaction system under turbulent wind is proposed based on the relevant theory of wind engineering and dynamics. Considering the fluctuating properties of wind field, the stochastic wind velocity time history is simulated by the Auto-Regressive method in terms of power spectral density function of wind field. The bridge is represented by three-dimensional finite element model and the vehicle by a multi-rigid-body system connected by springs and dashpots. The detailed calculation formulas of unsteady aerodynamic forces on bridge and vehicle are derived. In addition, the form selection of wind barriers, which are applied as the windbreak measures of newly-built railways in northwest China, is studied based on the suggested evaluation index, and the suitable values about height and porosity rate of wind barriers are studied. By taking a multi-span simply-supported box-girder bridge as a case study, the dynamic response of the bridge and the running safety indices of the train traveling on the bridge with and without wind barriers are calculated. The limit values of train speed with respect to different wind velocities are proposed according to the allowance values in the design code.

• The Research Journal of the Costume Culture
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• v.11 no.2
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• pp.219-230
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• 2003

The purpose of this study was to analyze the structure of consumption emotions that consumers experienced in the process of consuming apparel products. Data was collected from 144 female college students living in Busan, and analyzed by salience, diversity, H-index, Clamor's V, and multi-dimensional scaling. The results showed as following; 1. The consumption emotions related to apparel products appeared three dimensions; ‘Relaxed-tense’ dimension, ‘Pleasant-unpleasant’ dimension, and ‘Outward-inward’ dimension. Considering elements of consumption system, the dimensions of consumption emotions in relation to apparel performances were 'Pleasant-unpleasant' and ‘Outward-inward’. The dimensions of consumption emotions experienced in usage situations were ‘Relaxed-tense’ and ‘pleasant-unpleasant’. The consumption emotions related to specific products were composed of ‘Pleasant-unpleasant’ dimension and ‘Outward-inward’ dimension. 2. As the multi-dimension map of this study has much space, it suggested that the scope of consumption emotions related to apparel products was more limited than those related to general situations and products. 3. The structure of consumption emotions in relation to apparel performances appeared to be bisected, while those related to usage situations showed relatively to be dispersed. 4. Although Pleasant-unpleasant dimension was consistent with results of prestudies, the dimensions of ‘Relaxed-tense’ and ‘Outward-inward’ were newly confirmed as the dimensions of consumption emotions related to apparel products. Therefore, consumer's consumption emotions of apparel products were composed of three dimensions, tended to be more limited than those of general consumption situations and products, and differentiated across apparel performances, usage situation, and specific products.

• Journal of Information Technology Services
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• v.19 no.2
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• pp.93-107
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• 2020

Recently, artificial intelligence (AI) technologies has been widely used in various fields such as finance, and distribution. Accordingly, Korea has also announced its AI R&D strategy for the realization of i-Korea 4.0 in May 2018. However, Korea's AI technology is inferior to major competitors such as the US, Canada, and Japan Therefore, in order to cope with the 4th industrial revolution, it is necessary to allocate AI R&D budgets efficiently through selection and concentration so as to gain competitive advantage under a limited budget. In this study, the importance of each AI technology was evaluated in multi-dimensional way through the questionnaire of expert group using the evaluation index derived from the literature review From the results of this study, we draw the following implication. In order to successfully establish the AI technology development strategies, it is necessary to prioritize the cognitive computing technology that has great market growth potential, ripple effect of technology development, and the urgency of technology development according to the principle of selection and concentration. To this end, it is necessary to find creative ideas, manage assessments, converge multidisciplinary systems and strengthen core competencies. In addition, since AI technology has a large impact on socioeconomic development, it is necessary to comprehensively grasp and manage scientific and technological regulations in order to systematically promote AI technology development.

• Journal of Korea Multimedia Society
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• v.9 no.11
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• pp.1395-1409
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• 2006

A spatial data warehouse has spatial data cube composed of multi-dimensional data for efficient OLAP(On-Line Analytical Processing) operations. A spatial data cube supporting concept hierarchies holds huge amount of data so that many researches have studied a incremental update method for minimum modification of a spatial data cube. The Cube, however, compressed by eliminating prefix and suffix redundancy has coalescing paths that cause update inconsistencies for some updates can affect the aggregate value of coalesced cell that has no relationship with the update. In this paper, we propose incremental batch update method of a spatial data cube. The proposed method uses duplicated nodes and extended node structure to avoid update inconsistencies. If any collision is detected during update procedure, the shared node is duplicated and the duplicate is updated. As a result, compressed spatial data cube that includes concept hierarchies can be updated incrementally with no inconsistency. In performance evaluation, we show the proposed method is more efficient than other naive update methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.6
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• pp.1522-1545
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• 2012

Call admission control (CAC) plays an important role in mobile cellular network to guarantee the quality of service (QoS). In this paper, a dynamic hybrid CAC scheme with integrated cutoff priority and handoff queue for mobile cellular network is proposed and some performance metrics are derived. The unique characteristic of the proposed CAC scheme is that it can support any number of service types and that the cutoff thresholds for handoff calls are dynamically adjusted according to the number of service types and service priority index. Moreover, timeouts of handoff calls in queues are also considered in our scheme. By modeling the proposed CAC scheme with a one-dimensional Markov chain (1DMC), some performance metrics are derived, which include new call blocking probability ($P_{nb}$), forced termination probability (PF), average queue length, average waiting time in queue, offered traffic utilization, wireless channel utilization and system performance which is defined as the ratio of channel utilization to Grade of Service (GoS) cost function. In order to validate the correctness of the derived analytical performance metrics, simulation is performed. It is shown that simulation results match closely with the derived analytic results in terms of $P_{nb}$ and PF. And then, to show the advantage of 1DMC modeling for the performance analysis of our proposed CAC scheme, the computing complexity of multi-dimensional Markov chain (MDMC) modeling in performance analysis is analyzed in detail. It is indicated that state-space cardinality, which reflects the computing complexity of MDMC, increases exponentially with the number of service types and total channels in a cell. However, the state-space cardinality of our 1DMC model for performance analysis is unrelated to the number of service types and is determined by total number of channels and queue capacity of the highest priority service in a cell. At last, the performance comparison between our CAC scheme and Mahmoud ASH's scheme is carried out. The results show that our CAC scheme performs well to some extend.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.8 no.1
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• pp.12-17
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• 1997

Measuring phonatory stability using MDVP(Multi-dimensional voice program, Kay Elemetrics Corp., NJ, USA) are becoming popular in many Korean clinics and laboratories, yet questions about standardization and reference values have remained. The purpose of present study was to examine the effects of frequency and intensity variation on the results of acoustic analysis related to phonatory stability. Twenty young adults(ten females and ten males) were asked to sustain vowel /a/ for more than 3 seconds under 9 different pitch and loudness conditions. Using MDVP, nine voice samples were analyzed, and jitter percent, fundamental frequency variation, shimmer percent, peak amplitude variation, noise to harmonic ratio, amplitude tremor intensity index, and degree of subharmonics were compared. The results showed that intensity changes can significantly affect various phonatory stability measures, and the lowest perturbation values can be obtained from slightly louder(10dB) phonatory condition than comfortable level phonation.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.2
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• pp.10-18
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• 1997

This paper presents the development of real-time estimation and control details for a computer vision-based robot control method. This is accomplished using a sequential estimation scheme that permits placement of these points in each of the two-dimensional image planes of monitoring cameras. Estimation model is developed based on a model that generalizes know 4-axis Scorbot manipulator kinematics to accommodate unknown relative camera position and orientation, etc. This model uses six uncertainty-of-view parameters estimated by the iteration method. The method is tested experimentally in two ways : First the validity of estimation model is tested by using the self-built test model. Second, the practicality of the presented control method is verified in performing 4-axis manipulator's assembly task. These results show that control scheme used is precise and robust. This feature can open the door to a range of application of multi-axis robot such as deburring and welding.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.1-3
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• 2003

최근 중앙처리장치와 주기억장치간의 병목 현상에 의한 성능 저하를 극복하기 위해 캐시를 고려한 색인 구조들이 제안되었다. 이런 색인 구조들의 궁극적인 목표는 엔트리 크기를 줄여 팬-아웃(fan-out)을 증가시키고, 캐시 접근 실패를 최소화하여 시스템의 성능을 높이는 것이다. 엔트리의 크기를 줄이는 기법에 따라 기존의 색인 구조들을 두 가지로 구분할 수 있다. 하나는 좌표 값을 고정된 비트로 양자화 함으로써, MBR 키를 압축하는 것이다. 또 다른 하나는 MBR들의 각 좌표 값 중에 그들의 부모 MBR과 같지 않은 좌표 값만을 저장하는 것이다. 본 논문에서는 두 기법의 특성들을 적절히 합한 새로운 색인 구조를 제안하고, 기존에 제시된 두 접근법을 따르는 주기억장치 상주형 다차원 색인 구조를 다양한 환경에서 성능 평가한다. 또한, 기존의 색인 구조와 비교를 통해 제안하는 색인 구조의 우수성을 보인다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1993.11a
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• pp.97-102
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• 1993

According as the high integrity of the semi conductor devices is definited required, the concern on the multi-layered wiring, and three-dimensional devices is growing these days. Therefore, plasma-enhanced chemical vapored deposition(PECVD) enables low-teperature process and is widely used, but it causes the instability of the devices due to a lot of impurities within the film. The PECVD oxynitride was formed by changing the gas ratio of (N$_2$O) to (N$_2$+NH$_3$). It's contained a small portion of hydrogen, had higher refrctive index and capacitance than oxide, and showed the capacitance increasement and the chemical stabi1ity. This is caused by nitrogen distribution increase of the interface lather than within the film.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04b
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• pp.131-133
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• 2000

이 논문에서는 다차원 색인 구조에서 질의를 지연시키는 주된 요인인 노드 분할연산과 MBR(Minimun Bounding Regions)변경 연산에 대해 효율적으로 대처하는 동시성 제어 기법을 제안한다. 분할 시 탐색이 지연되는 시간을 최소화 하기 위해 대부분의 과정에서 질의와 호환되는 공유 래치를 획득한 후 수행하고 분할이 발생된 노드에 엔트리들이 복사되는 동안만 배타 래치를 획득하는 방법을 사용한다. MBR 변경 연산의 동시성을 높이기 위해 부분적인 잠금 결합을 사용한다. 즉, MBR 변경 연산중 주로 발생되는 MBR이 증가되는 삽입연산은 잠금 결합을 수행하지 않고, 감소되는 삭제 연산만 잠금 결합을 수행한다. 또한 성능 평가를 통하여 제안된 동시성 제어 기법이 GiST의 동시성 제어 알고리즘에 비해 처리율 관점에서 성능이 우수함을 보인다.