• 한국IT서비스학회지
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• 제9권2호
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• pp.163-177
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• 2010

In this paper, we consider a channel ordering problem that seeks to maximize the service quality in mobile radio communication systems. If a base station receives a connection request from a mobile user, one of the empty channels belonging to the base station is assigned to the mobile user. In case multiple empty channels are available, we can choose one that incurs least interference with other channels assigned to adjacent base stations. However, note that a pair of channels that are not separated enough generates interference only if both channels are assigned to mobile users. That is, interference between channels may vary depending on the channel assignment sequence for each base station and on the distribution of mobile users. To find a channel assignment sequence that seems to generate minimum interference, we develop an optimization model considering various scenarios of mobile user distribution. Simulation results show that channel assignment sequence determined by the scenario based optimization model significantly reduces the interference provided that scenarios and interference cost are properly generated.

• 한국농공학회지
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• 제22권3호
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• pp.75-87
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• 1980

Most hydro]ogic phenomena are the complex and organic products of multiple causations like climatic and hydro-geological factors. A certain significant correlation on the run-off in river basin would be expected and foreseen in advance, and the effect of each these causual and associated factors (independant variables; present-month rainfall, previous-month run-off, evapotranspiration and relative humidity etc.) upon present-month run-off(dependent variable) may be determined by multiple regression analysis. Functions between independant and dependant variables should be treated repeatedly until satisfactory and optimal combination of independant variables can be obtained. Reliability of the estimated function should be tested according to the result of statistical criterion such as analysis of variance, coefficient of determination and significance-test of regression coefficients before first estimated multiple regression model in historical sequence is determined. But some error between observed and estimated run-off is still there. The error arises because the model used is an inadequate description of the system and because the data constituting the record represent only a sample from a population of monthly discharge observation, so that estimates of model parameter will be subject to sampling errors. Since this error which is a deviation from multiple regression plane cannot be explained by first estimated multiple regression equation, it can be considered as a random error governed by law of chance in nature. This unexplained variance by multiple regression equation can be solved by stochastic approach, that is, random error can be stochastically simulated by multiplying random normal variate to standard error of estimate. Finally hybrid model on estimation of monthly run-off in nonhistorical sequence can be determined by combining the determistic component of multiple regression equation and the stochastic component of random errors. Monthly run-off in Naju station in Yong-San river basin is estimated by multiple regression model and hybrid model. And some comparisons between observed and estimated run-off and between multiple regression model and already-existing estimation methods such as Gajiyama formula, tank model and Thomas-Fiering model are done. The results are as follows. (1) The optimal function to estimate monthly run-off in historical sequence is multiple linear regression equation in overall-month unit, that is; Qn=0.788Pn+0.130Qn-1-0.273En-0.1 About 85% of total variance of monthly runoff can be explained by multiple linear regression equation and its coefficient of determination (R2) is 0.843. This means we can estimate monthly runoff in historical sequence highly significantly with short data of observation by above mentioned equation. (2) The optimal function to estimate monthly runoff in nonhistorical sequence is hybrid model combined with multiple linear regression equation in overall-month unit and stochastic component, that is; Qn=0. 788Pn+0. l30Qn-1-0. 273En-0. 10+Sy.t The rest 15% of unexplained variance of monthly runoff can be explained by addition of stochastic process and a bit more reliable results of statistical characteristics of monthly runoff in non-historical sequence are derived. This estimated monthly runoff in non-historical sequence shows up the extraordinary value (maximum, minimum value) which is not appeared in the observed runoff as a random component. (3) "Frequency best fit coefficient" (R2f) of multiple linear regression equation is 0.847 which is the same value as Gaijyama's one. This implies that multiple linear regression equation and Gajiyama formula are theoretically rather reasonable functions.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.422-425
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• 2001

The realization of the avoidance, decrease and utilization of waste can be made through reduction of resource consumption during product production and use. Beside that it is desirable to regain the resource attached to products and components. The same resources can be much used in product and mater all cycle through their reuse and regeneration In order to improve the use productivity of resource the disassembly make up the substantial prerequisite. In this paper a model describing the disassembly sequence structure is introduced under consideration of the influential facts related to disassembly process planning rules for disassembly sequence planning are derived from that.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 추계 학술논문 발표대회
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• pp.196-197
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• 2015

In tall building construction, time for transporting form affects formwork duration as plan size has become larger and quantity of inputted form has been increased. Thus, necessity of systematic dismantlement sequence of form has been increased to reduce the duration of formwork. Tabu search has been efficiently applied to solve problem of combinatorial optimization by using tabu list which can improve combination values. Therefore, this study proposes optimization model of dismantlement sequence of table form which has been preferred in tall building construction, to reduce the formwork duration by minimizing time for transporting form.

• Food Science and Biotechnology
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• 제17권5호
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• pp.1052-1059
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• 2008

Sequential Sensitivity Analysis (SSA) and conditional stimulus model have been developed to describe sequence effects in difference tests and proposed to generate prediction of differences in sensitivity between various test protocols and to assist the appropriate selection of difference test. Yet, such models did not furnish a complete explanation of the relative sensitivity in 4 different versions of 3-alternative forced choice (AFC) tests where various interstimulus rinses were introduced. In the present study, the vector of the contrasts between various conditional stimuli were measured using same-different and 2-AFC and a new 16-distribution conditional stimulus model was developed by refining Lee and O'Mahony's contrast model. This new model gave superior predictions than previous models.

• Structural Engineering and Mechanics
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• 제52권5호
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• pp.919-935
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• 2014

In this study, the control of the shape of pre-stressed cable structures and the effective control element were examined. The process of deriving the displacement control equations using the force method was explained, and the concurrent control scheme (CCS) and the sequence control scheme (SCS) were proposed. To explain the control scheme process, the quadrilateral cable net model was adopted and classified into a regular model and an irregular model for the analysis of the control results. In the control analysis of the regular model, the CCS and SCS analysis results proved reliable. For the SCS, the errors occur in the control stage and varied according to the control sequence. In the control analysis of the irregular model, the CCS analysis result also proved relatively reliable, and the SCS analysis result with the correction of errors in each stage was found nearly consistent with the target shape after the control. Finally, to investigate an effective control element, the Geiger cable dome was adopted. A set of non-redundant elements was evaluated in the reduced row echelon form of a coefficient matrix of control equations. Important elements for shape control were also evaluated using overlapping elements in the element sets, which were selected based on cable adjustments.

• Geomechanics and Engineering
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• 제15권3호
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• pp.911-917
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• 2018

This paper concerns a numerical investigation on the effect of construction sequence on three-arch (3-Arch) tunnel behavior. A three-arch tunnel section adopted in a railway tunnel construction site was considered in this study. A calibrated 3D finite element model was used to conduct a parametric study on a variety of construction scenarios. The results of analyses were examined in terms of tunnel and ground surface settlements, shotcrete lining stresses, loads and stresses developed in center column in relation to the tunnel construction sequence. In particular, the effect of the side tunnel construction sequence on the structural performance of the center structure was fully examined. The results indicated that the load, thus stress, in the center structure can be smaller when excavating two side tunnels from opposite direction than excavating in the same direction. Also revealed was that no face lagging distance between the two side tunnels impose less ground load to the center structure. Fundamental governing mechanism of three-arch tunnel behavior is also discussed based on the results.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1307-1312
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• 2009

Design is an act based on multidisciplinary information. The involvement of various stakeholders makes it difficult to process, plan, and integrate. Iteration is frequent in most of the engineering design and development projects including construction. Design iterations cause rework, and extra efforts are required to get the optimal sequence and to manage the projects. The simple project management techniques are insufficient to fulfill the requirements of integrated design. This paper entails two things: design structure matrix and design parameters' information based model. The emphasis has been given to optimal sequence and crucial iteration using design structure matrix analysis technique. The design projects have been studied using survey data from industry. The optimal sequence and crucial iterations results have been utilized for proposed model. Model integrates two things: information about produced- required key design parameters and information of design changes during the design process. It will help to get familiar with Design management in order to fulfill contemporary needs.

• Ecology and Resilient Infrastructure
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• 제7권1호
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• pp.53-62
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• 2020

본 연구는 복원기법을 다양하게 조성하였을 때 어류의 서식처의 변화를 파악하기 위하여 물리서식처 모의를 수행하였다. 대상 구간은 원주천이며, 대상 어종은 돌고기, 피라미, 참갈겨니를 대상으로 하였다. 흐름 분석은 2차원 모형인 River2D 모형을 사용하였으며, 서식처 분석은 서식처 적합도 곡선을 이용하여 서식처의 양과 질을 산정하는 서식처 적합도 모형을 사용하였다. 생태학적으로 적합한 여울-소 출현에 따른 서식처의 변화를 확인하기 위하여 조성 구간을 50 m, 100 m, 200 m, 300 m으로 설정하였다. 그 결과 대상 어종별로 약간의 차이는 발생하였지만, 여울-소 복원기법을 200 m 구간으로 설정하였을 때 서식처가 현상태와 비교하였을 때 가중가용면적이 약 53% 향상되는 것으로 나타났다.

• 한국항해항만학회지
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• 제31권8호
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• pp.711-716
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• 2007

컨테이너에 화물을 적재함에 있어서 고려해야할 점으로 컨테이너의 적재율을 들 수 있다. 단순히 제한된 공간에 보다 많은 양의 화물을 적재하여 비용을 낮추고자 하는 노력은 꾸준히 계속되어 왔다. 하지만 방문순서를 고려해야만 하는 화물의 경우는 다르다. 조선기자재와 같은 대형 화물들의 경우 방문순서를 고려하지 않았을 경우 하역작업에서 화물 재 조작 또는 하역 작업이 불가능한 상황이 발생할 수 있기 때문이다. 본 연구에서는 화물 적재 시 방문 순서를 고려하는 문제를 해결하고자 하며, 이에 방문 순서와 적재율을 동시에 고려한 컨테이너 혼재모형과 그 해법을 제시하고자 한다.