• 대한산업공학회지
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• 제26권3호
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• pp.227-237
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• 2000

A workflow management system is a software system to assist designing processes, controlling and managing the execution of the designed processes. One emerging trend in many recent information systems is the provision of process management functions. In this paper, we propose a method of designing processes for automatic process execution directly from process modeling. First of all, the concept of block is presented which is to define a nested process model. A block is the minimum unit that can specify the relationships of process components, i.e., tasks. A general process can be defined by a combination of the blocks defined in this paper. An algorithm is developed to transform a general flat process model into a nested model. We identify basic types of blocks and build ECA (Event-Condition-Action) rules for each of the basic types. This allows us to automate the execution of the process model by using the active features of active databases.

• 대한산업공학회지
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• 제31권2호
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• pp.173-179
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• 2005

This paper presents an extended EMQ model which determines an optimal production quantity for a single stage production system when defective items are stochastically produced in the production process and they are re-processed in the rework process to convert them into non-defectives. Through the mathematical modeling, an optimal solution minimizing the average cost per unit time and minimum average cost as well as some properties are derived. It can be shown that each of the existing models is a special case of the proposed model under some conditions. Numerical experiment is carried out to examine the behavior of the proposed model and support properties derived.

• Journal of Electrical Engineering and information Science
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• 제2권6호
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• pp.43-47
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• 1997

A procedure presented in this paper generates test sequences to check the conformity of an implementation with a protocol specification, which is modeled as a deterministic finite state machine (FSM). Given a FSM, a common procedure of test sequence generation, first, constructs a directed graph which edges include the state check after each transition, and produces a symmetric graph G* from and, finally, finds a Euler tour of G*. We propose a technique to determine a minimum-cost tour of the transition graph of the FSM. The proposed technique using Multiple Unique State Signature (MUSS) solves an open issue that one MUIO sequence assignment may lead to two more edges of unit cost being replicated to from G* while an optimal assignment may lead to the replication of a single edge of high cost. In this paper, randomly generated FSMs have been studied as test cases. The result shows that the proposed technique saves the cost 4∼28% and 2∼21% over the previous approach using MUIO and MUSP, respectively.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.161-168
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• 2003

In the drift design of high-rise buildings, once the geometry and dimensions of a structure are predetermined, engineer's remaining work is determination of the member size to satisfy the strength and the stiffness requirements. For the case of highrise buildings, designs are determined by the stiffness requirements at the final stage of structural design. Thus, engineers try to find a minimum weight design with maximum lateral stiffness. However, there is no guideline for engineers on the required weight of structures per unit area to satisfy the stiffness requirements. In this study, drift design method considering weight modification factors are presented and applied to a 20-story structure. The proposed drift design method considering weight modification factors may give the guideline for engineers on the amount of structural weight to attain target displacement.

• 한국광물학회지
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• 제4권2호
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• pp.90-98
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• 1991

This study introduces a new structural model of 1M 2:1 trioctahedral clay minerals or, more generally, 2:1 trioctahedral phyllosilicates. The structural model requires only the chemical formulae of the clay minerals as an input and uses the regression relation (Radoslovich, 1962) to calculate the a- and b-dimensions of the phyllosilicates with the given chemical formulae. The atomic coordinates of the constituent atoms are geometrically calculated for C2/m space group under the assumption that the interatomic distances are constant. To determine the c-dimension, this study calculates the binding energies of 1M 2:1 trioctahedral phyllosilicates as a function of d(001) and find the minimum energy producing d(001). The structural model generates the cell dimensions, interaxial angles, interatomic distances, octahedral, tetrahedral and interlayer thickness, polyhedron deformation angles and atomic coordinates in the unit cell. The simulated structural parameters of phlogopite and annite are very close to the reported data by Hazen and Burnham (1973), suggesting that the structure simulation using only the chemical formule is successful, and thus, that the structural model of this study overcomes the difficulties in the previous models by other investigators.

• 전기의세계
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• 제17권1호
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• pp.21-31
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• 1968

The variation of the voltage has been known to be harmful in the sound operation of motors. It also results in the variation in slip. If the voltage and slip are known, every characteristics of motors can be determined. This paper, therefore, analyzed numerically the characteristics of motors by the formula expressed in the function of both slip and voltage, and then satisfactorily compared with the experimental values. A new per-unit method derived in this paper is shown to be easier and simpler than the conventnional one in determining the relative running characteristics. It has also suggested the minimum allowable voltage when voltage below the rated value was applied to the motor. It is expected to apply to the determination of the characteristics under the voltage variation.

• 대한산업공학회지
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• 제40권2호
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• pp.233-239
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• 2014

This paper presents an extended EMQ model which determines an optimal production run length in an deteriorating production process. The production process is subject to a random deterioration from an in-control state to an out-of-control state and thus producing some proportion of defective items. Defective items produced are re-processed in the rework process to convert them into non-defectives. Through the mathematical modeling, an optimal solution minimizing the average cost per unit time as well as minimum average cost are derived. Numerical experiment is carried out to examine the behavior of the proposed model depending on model parameters.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.323-325
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• 1996

The design of Intelligent Energy Saving Power System Controller (IESPSC) for Telecom DC power plants is proposed and presented in this paper. From the past experience. rectifiers for Telecom DC power plants have been operated inefficiently at light loads. IESPSC offers "novel load sharing" approach based on the knowledge of each unit's efficiency of paralleled rectifiers. Neural networks is used for identifying each rectifier's efficiency characteristic curve corresponding to load currents, which is in turn utilized to produce a system efficiency close to the maximum under all operating conditions. In addition, by limiting the number of operating units to the minimum while maintaining high efficiency at the determined loads, a drastic savings in operating cost can be achieved.

• 한국가구학회지
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• 제13권2호
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• pp.75-84
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• 2002

The chairs are one of the most important furniture in this modern society, as we know that history of furniture is made of history of the chairs. Among the chairs, the stool, which made by only sit and legs, forms the basis of the chairs. The stool plays an important part in the human body to support and also help to make an agile movement In a short period of time. The stool is the minimum unit of chair, which made of least size and simple structure; therefore it fits to study basic knowledge of furniture making. For that reason, we can see occasionally the schools of furniture design departments have chosen the stool making course in their foundation students' studio classes. However, the professional study on the stool, such as the study on the posture for designing stool, has not been developed yet. This study presents basic Information of design for stool by analyzing various stools formatively.

• Journal of Electrical Engineering and Technology
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• 제11권4호
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• pp.860-868
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• 2016

A bidirectional DC-DC converter (BDC) is an indispensable electrical unit for the electric vehicles (EVs). High efficiency, high power density, isolation, light weight and reliability are all essential requirements for BDC. In this paper, a 3 kW BDC for the battery charger of EVs is proposed. The proposed converter consists of a half-bridge structure on the primary side and an isolation transformer and a synchronous rectifier structure on the secondary side. With this topology, minimum number of switching devices are required for bidirectional power flow between the two dc buses of EVs. The easy implementation of the synchronous rectification gives advantages in terms of efficiency, cost and flexibility. The proposed BDC achieves high efficiency when operating in both modes (step-up and step-down). A 3 kW prototype is implemented to verify theoretical analysis and the performance of the proposed converter.