• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.469-475
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• 1991

In this paper, we suggest the exact perturbation analysis(Exact_PA) technique with respect to the buffer storage in tandem queueing networks, through which the optimal buffer storage design problem is considered. The discrete event dynamic equations for the departure time of a customer are presented together with the basic properties of Full Out(FO) and No Input(NI) with respect to the buffer storage. The new perturbation rules with respect to the buffer storage are suggested, from which the exact perturbed path can be obtained. The optimal buffer storage problem is presented by introducing a performance measure consisting of the throughput and the buffer storage cost. An optimization algorithm maximizing this performance measure is derived by using the Exact_PA technique. The proposed perturbation analysis technique and the optimization algorithm are validated by numerical examples.

• 대한음성학회:학술대회논문집
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• 대한음성학회 1996년도 10월 학술대회지
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• pp.224-228
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• 1996

This paper is intended as a study on how an utterance is divided into rhythmic units in Standard Korean with respect to its syntactic structure. With respect to the data in this study I used 150 sentences which contained similar number of words and various syntactic structures. Those sentences were read by 7 speakers of Seoul dialect in a conversation style. Each sentence was read twice in a normal speed and twice in a fast speed. As a total, 4200 sentences were recorded. Then listening to them, the author marked the sentences with two kinds of boundaries i.e. strong and weak. To explore the relationship between rhythmic units and syntactic structure I devised a framework of grammatical symbols. Each symbol is designed to have both syntactic and morphological information at the same time. So I assigned those grammatical symbols to the sentences. Having sentences marked with grammatical symbols on the one hand, and with the rhythmic boundaries on the other hand, 1 could show the relationship between rhythmic units and syntactic structure; which syntactic structures are likely to be pronounced as one rhythmic unit, and which are on the rhythmic boundaries.

• 동력기계공학회지
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• 제18권5호
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• pp.150-155
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• 2014

This paper presents The performance analysis of inverter control type-industrial cooler with respect to refrigeration load and outdoor temperature. Aside from materials about simulations and foundation data regarding inverter control compressors, currently, data about commercial coolers with inverter control still lack information for performance comparison. Thus, in this paper, the experiments are done to see characteristics of condensation capacity, evaporation capacity, compressor power and COP with respect to outdoor temperature and load by using a commercial inverter control cooler model. As a result, COP difference of the inverter control cooler with respect to load is 30% at the outdoor temperature of $35^{\circ}C$, 29% at the outdoor temperature of $30^{\circ}C$, 34% at $25^{\circ}C$, respectively.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.701-705
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• 2008

Design analysis and computer experiments (DACE) model is widely used to express efficiently the nonlinear responses in the field of engineering design. Kriging model, a DACE model, can approximately replace a simulation model that is very expensive or highly nonlinear. The kriging model is composed of the summation of a global model and a local model representing deviation from global model. The local model is determined by correlation coefficient of the pre-sampled points, where determination of the correct correlation coefficient has an effect on accuracy and robustness of the kriging model. Therefore, robustness of the correlation coefficient is explored with respect to degrees of the global model. Then we propose the range of correlation coefficient to make correct and robust kriging model and the influence of the correlation coefficients on the degrees of global model with respect to the nonlinearity of the pre-sampled responses.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.343-348
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• 2011

This paper presents ride comfort characteristics of a quarter-vehicle magneto-rheological (MR) suspension system with respect to different tire pressure. As a first step, controllable MR damper is designed and modeled based on both the optimized damping force levels and mechanical dimensions required for a commercial full-size passenger vehicle. Then, a quarter-vehicle suspension system consisting of sprung mass, spring, tire and the MR damper is constructed. After deriving the equations of the motion for the proposed quarter-vehicle MR suspension system, vertical tire stiffness with respect to different tire pressure is experimentally identified. The skyhook controller is then implemented for the realization of the quarter-vehicle MR suspension system. Finally, the ride comfort analysis with respect to different tire pressure is undertaken in time domain. In addition, a comparative result between controlled and uncontrolled is provided by presenting vertical RMS displacement.

• Kyungpook Mathematical Journal
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• 제55권2호
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• pp.429-438
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• 2015

The objective of this paper is to obtain sharp upper bound for the second Hankel functional associated with the $k^{th}$ root transform $[f(z^k)]^{\frac{1}{k}}$ of normalized analytic function f(z) when it belongs to the class of starlike and convex functions with respect to symmetric points, defined on the open unit disc in the complex plane, using Toeplitz determinants.

• 전자공학회논문지S
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• 제35S권10호
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• pp.85-93
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• 1998

선형 시스템의 출력 조절 문제에 있어서, 출력 조절가능성은 일반적으로 보존되지 않는다. 따라서, 연속시간 선형시스템에 대해 설계된 아날로그 조절기를 샘플링하여 구현한 디지털 출력조절기는, 샘플링 시간에 대해 1차 근사적인 근사 샘플치 조절기에 불과하다. 그런데, 주어진 시스템의 내재적 구조를 잘 이용하면, 샘플링 시간에 대해 개선된 근사 샘플치 출력 조절기 설계가 가능하다. 본 논문은 샘플링 시간에 대해 더 개선된 근사 샘플치 출력 조절기를 설계하기 위한 시스템의 구조를 연구하였다.

• Journal of Construction Engineering and Project Management
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• 제7권3호
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• pp.15-25
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• 2017

The existence of material price volatility in construction projects puts forward substantial risks for all parties involved. Depending on the parties involved in the project, type of contracts, and state of the market various risk management strategies are practiced by contracting parties to manage project risks related to price volatility. Unfortunately, in many cases companies fail to select an adequate approach to better manage volatilities of material prices due to the lack of a decision support system to aid in the selection of an appropriate strategy based on the project characteristics. The aim of this study is to identify critical project factors and align them to documented strategies to manage price volatility based on an extensive literature review and industry interviews. This study found Integrated Project Delivery (IPD) as the ideal strategy with respect to project duration; quantitative risk management methods with respect to the cost; and Price Adjustment Clauses (PAC) with respect to the risk allocation, as the top price volatility management strategies.

• Smart Structures and Systems
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• 제8권2호
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• pp.157-172
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• 2011

A new method for both local damage(s) identification and input excitation force identification of beam structures is presented using the dynamic response sensitivity-based finite element model updating method. The state-space approach is used to calculate both the structural dynamic responses and the responses sensitivities with respect to structural physical parameters such as elemental flexural rigidity and with respect to the force parameters as well. The sensitivities of displacement and acceleration responses with respect to structural physical parameters are calculated in time domain and compared to those by using Newmark method in the forward analysis. In the inverse analysis, both the input excitation force and the local damage are identified from only several acceleration measurements. Local damages and the input excitation force are identified in a gradient-based model updating method based on dynamic response sensitivity. Both computation simulations and the laboratory work illustrate the effectiveness and robustness of the proposed method.

• 산업기술연구
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• 제18권
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• pp.399-404
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• 1998

The purposes of this research were constructed the database, based on graphing the present water pollution in Han-river due to livestock wastewater(LSW). The LSW was below 1% in respect to quantity but about 7% in respect to pollutants loading in overall Han-river. The ratio of untreated LSW is 18% to 28%, which was higher compared to the municipal and industrial wastewater. In other words, LSW was about 0.05 times of municipal wastewater in respects to quantity but 2 times in respect to the ratio of untreated wastewater. So, it was necessary for treating LSW. The pollutants loading due to livestock wastewater of the South Han-river, North Han-river and main stream were 19.7%, 19.4% and 4.0%, respectively. This was about 7% in overall Han-river. We separated the Han-river into upper, mid and down stream. As a result, we found that the livestock wastewater is the main water pollution source of upper Han-river.