• 한국경영과학회지
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• 제19권3호
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• pp.139-149
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• 1994

In many project-oriented production systems, e. g., shipyards or large-scale steel products manufacturing, resource loading by an activity is flexible, and the activity duration is a function of resource allocation. For example, if one doubles the size of the crew assigned to perform an activity, it may be feasible to complete the activity in half the duration. Such flexibility has been modeled by Weglarz [13] and by Leachman, Dincerler, and Kim [7[ in extended formulations of the resource-constrained poject scheduling problem. This paper presents a new algorithmic approach to the problem that combines the ideas proposed by the aforementioned authors. The method we propose involves a two-step approach : (1) solve the resource-constrained scheduling problem using a heuristic, and (2) using this schedule as an initial feasible solution, find improved resource allocations by solving a linear programming model. We provide computational results indicating the superiority of this approach to previous methodology for the resource-constrained scheduling problem. Extensions to the model to admit overlap relationship of the activities also are presented.

• 한국해양공학회지
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• 제26권4호
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• pp.8-14
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• 2012

Two dimensional nesting is a common problem in industries such as the shipbuilding, automotive, clothing, shoe-making, and furniture industries, in which various parts are cut off from stock or packed in a flat space while minimizing waste or unoccupied space. Nesting is known as an NP-complete problem, which has a solution time proportional to the superpolynomial of the input size. It becomes practically impossible to find an optimal solution using algorithmic methods as the number of shapes to nest increases. Therefore, heuristic methods are commonly used to solve nesting problems. This paper presents an expert system that uses a heuristic search method based on an evaluation function for nesting problems, in which parts and stock are represented by pixels. The system is developed in CLIPS, an expert system shell, and is applied to four different kinds of example problems to verify its applicability in practical problems.

• 산업공학
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• 제13권3호
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• pp.320-327
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• 2000

In this research report, we consider multi stage supply chain optimization modeling techniques, and propose a new integrated model. The stages that are normally associated with a supply chain include procurement, production and distribution. In general, there are two distinct set of approaches which manage whole supply chain. One approach is the plant decision and subsequently distribution and inventory decision while the second approach is to address all decisions simultaneously through the integrated model. First, we present a survey of existing models that are treated by independently. And then, we propose an integrated model that is in a moderate size and easy to implement in practice. Finally, we address possible solution methodologies and present some computational test results using CPLEX to see the computational burden from which new algorithmic insight might be come up.

• 대한산업공학회지
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• 제19권3호
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• pp.139-154
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• 1993

Cutter Interference(or part surface gouging) is one of the most critical problems in NC machining of sculptured surfaces. Presented in this paper is and algorithmic procedure that converts CC data obtained from a compound surface(several surfaces without topological relationship) into interference-free CL data. The interference handling procedure consists of following steps: (1) Z-map model is constructed from input surfaces. (2) Interference sources are detected using local properties of the sources. (3) Interference regions are completely identified based on global tests for neighboring CC points of the interference sources (4) Cutter paths are reconstructed after removing the CC data in interference regions, while avoiding any new interferences.

• 한국멀티미디어학회논문지
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• 제23권6호
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• pp.756-764
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• 2020

A typical algorithm used for image analysis is the Convolutional Neural Network(CNN). R-CNN, Fast R-CNN, Faster R-CNN, etc. have been studied to improve the performance of the CNN, but they essentially require large amounts of data and high algorithmic complexity., making them inappropriate for small and medium-sized services. Therefore, in this paper, the image label prediction algorithm based on CNN with collaborative layer with low complexity, high accuracy, and small amount of data was proposed. The proposed algorithm was designed to replace the part of the neural network that is performed to predict the final label in the existing deep learning algorithm by implementing collaborative filtering as a layer. It is expected that the proposed algorithm can contribute greatly to small and medium-sized content services that is unsuitable to apply the existing deep learning algorithm with high complexity and high server cost.

• Journal of information and communication convergence engineering
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• 제9권5호
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• pp.607-609
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• 2011

In this work, we present solutions of two problems. First, the representation of pattern recognition problem in the standard $T_{nml}$ table of the algorithm estimate calculation was considered. Second, the problem of finding the model, consisting of the optimal parameters of an algorithm was considered. Such procedure is carried out by the selection optimal values of the parameters of extreme algorithms. This serves to reduce the number of calculations in the algorithms of estimate calculation and to increase the quality of recognition process. The algorithmic data base of the developed system was based on mathematical apparatus of pattern recognition.

• Childhood Kidney Diseases
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• 제21권2호
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• pp.53-60
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• 2017

Proteinuria is common in pediatric and adolescent patients. Proteinuria is defined as urinary protein excretion at levels higher than $100-150mg/m^2/day$ in children. It can be indicative of normal or benign conditions as well as numerous types of severe underlying renal or systemic disease. The school urine screening program has been conducted in Korea since 1998. Since then, numerous patients with normal or benign proteinuria as well as early stage renal diseases have been referred to the hospital. Benign proteinuria includes orthostatic proteinuria and transient proteinuria. Most causes of proteinuria can be categorized into 3 types: 1) overflow, 2) tubular, and 3) glomerular. Although treatment should be directed at the underlying cause of the proteinuria, prompt evaluation, diagnosis, and long-term monitoring of these pediatric patients can prevent potential progression of the underlying disease process. This article provides an overview of proteinuria: its causes, methods of assessment, and algorithmic suggestions to differentiate benign from pathologic renal disease.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
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• pp.100-103
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• 1996

Presented in this study is an algorithmic procedure to obtain polyhedral model from a compound surface. The compound surface in this study denotes a collection of trimmed surfaces without topological relations. The procedure consists of two main modules: CAD data interface, and surface conversion to polyhedral model. The interface module gets geometric information from CAD databases, and makes topological information by scanning the geometric information. We are investigating CATIA system as a data source system. In the surface conversion module, a shell(compound surface with topological information) is approximated to a triangular-faceted polyhedral surface model through node sampling and triangulation steps. The obtained polyhedral model should obey the vertex-to-vertex rule and meet tolerance requirements. Since the polyhedral model has a simple data structure and geometry processing for it is very efficient and robust, the polyhedral model can be used in various applications, such as surface rendering in computer graphics, FEM model for engineering analysis, CAPP for surface machining, data generation for SLA, and NC tool path generation.

• 대한수학회지
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• 제38권4호
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• pp.807-842
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• 2001

This paper summarizes recent development of analytical and algorithmical results for stationary FIFO queues with multiple Markovian arrival streams, where service time distributions are general and they may differ for different arrival streams. While this kind of queues naturally arises in considering queues with a superposition of independent phase-type arrivals, the conventional approach based on the queue length dynamics (i.e., M/G/1 pradigm) is not applicable to this kind of queues. On the contrary, the workload process has a Markovian property, so that it is analytically tractable. This paper first reviews the results for the stationary distributions of the amount of work-in-system, actual waiting time and sojourn time, all of which were obtained in the last six years by the author. Further this paper shows an alternative approach, recently developed by the author, to analyze the joint queue length distribution based on the waiting time distribution. An emphasis is placed on how to construct a numerically feasible recursion to compute the stationary queue length mass function.

• 한국경영과학회지
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• 제16권2호
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• pp.128-147
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• 1991

We propose a dynamic incidence matrix (DIM) for reflecting states and time conditions of a timed Petri net (TPN) explicitly. Since a DIM consists of a conventional incidence matrix, two time-related vectors and two state-related vectors, we can get the advantages inherent in the conventional incidence matrix of describing a static structure of a system as well as another advantage of expressing time dependent state transitions. We introduce an algorithm providing the DIM with a state transition mechanism. Because the algorithm is, in fact, an algorithmic model for discrete event simulation of TPN models, we provide a theoretical basis of model transformation of a TPN model into a DEVS(Discrete Event system Specification) model. By executing the algorithm we can carry out performance analysis of computer communication protocols which are represented TPN models.