• Steel and Composite Structures
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• 제4권6호
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• pp.419-435
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• 2004

The safety level of a structural system designed per code specifications can not be inferred directly from the reliability of members due to the load redistribution and nonlinear inelastic structural behavior. Comparison of the system and member reliability, which is scarce in the literature, is likely to indicate any possible inconsistency of design codes in providing safe and economical designs. Such a comparative study is presented in this study for moment resisting two-dimensional steel frames designed per AISC LRFD Specifications. The member reliability is evaluated using the resistance of the beam-column element and the elastic load effects that indirectly accounts for the second-order effects. The system reliability analysis is evaluated based on the collapse load factor obtained from a second-order inelastic analysis. Comparison of the system and member reliability is presented for several steel frames. Results suggest that the failure probability of the system is about one order of magnitude lower than that of the most critically loaded structural member, and that the difference between the system and member reliability depends on the structural configuration, degree of redundancy, and dead to live load ratio. Results also suggest that the system reliability is less sensitive to initial imperfections of the structure than the member reliability. Therefore, the system aspect should be incorporated in future design codes in order to achieve more reliability consistent designs.

• 한국경영과학회지
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• 제30권2호
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• pp.117-129
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• 2005

This paper considers a make-to-order inventory-production system in which customer orders are admitted only when the number of outstanding customer orders is below a value committed by the system. We deal with general distributions for the customer order Inter-arrival, production, and replenishment lead time processes. Monotonicities of the optimal average cost with respect to these distribution parameters are established using sample path coupling arguments. When distributions are given as an exponential one, we implement a sensitivity analysis on the optimal inventory policy and show that it has monotonicities with respect to system costs using dynamic programming.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2003년도 춘계종합학술대회논문집
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• pp.149-154
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• 2003

21세기가 도래하면서 초고속 인터넷망의 발달과 더불어 편리함을 더욱 추구하고자 인터넷 주문 시스템이 발달 되어가고 있다. 현재 인터넷으로 음식 주문하는 시스템이 많이 개발되어 있지만 언제 어디서나 자신이 편한 곳에서 주문하고자 하는 소비자의 욕구에 충족하기 위하여 이동성이 확보된 무선 인터넷 단말기 (PDA, Pocket PC, HPC 등) 를 이용한 음식 주문시스템과 유선으로 주문 할 수 있는 시스템이 필요하다. 본 논문에서는 CTI를 기반으로 한 유/무선 인터넷 음식 주문 시스템을 설계하고 구현 하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 A
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• pp.302-304
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• 1992

This paper presents the method to reduce the order of high-order linear time invarient system via Walsh function. It is based on the matrix pseudoinverse algorithm to determine the parameters of the reduced model which minimize the sum of the squares of the errors between the reponses of the high-order system and a reduced model to a given input. This proposed method can be conveniently implemented with a computer. They will be very useful in the study of control system via Walsh function.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권11호
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• pp.650-653
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• 2005

In this paper, adaptive high-order neural network controller(AHONNC) is adopted to control an induction servomotor. A algorithm is developed by combining compensation control and high-order neural networks. Moreover, an adaptive bound estimation algorithm was proposed to estimate the bound of approximation error. The weight of the high-order neural network can be online tuned in the sense of the Lyapunov stability theorem; thus, the stability of the closed-loop system can be guaranteed. Simulation results for induction servomotor drive system are shown to confirm the validity of the proposed controller.

• 산업경영시스템학회지
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• 제34권4호
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• pp.1-10
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• 2011

This paper addresses the analysis of the travel distance and order picking time of the vehicle in a aisle when items are picked by the batch in a warehouse system. Batching is to combine several orders in a single tour of the storage/retrieval machine. An advantage of batching is that the length of a tour for a batch of orders is shorter than the sum of the individual orders' tour lengths. The average travel distance and order picking time when a batch is picked in a aisle of the warehouse systems are analyzed for the batch size. And when the vehicle is idle, the dwell point of the vehicle to minimize to the response distance is analyzed. As the batch size is increased, average order picking time per item is decreased. The problem is analyzed and a numerical example is showed to explain the problem.

• Nonlinear Functional Analysis and Applications
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• 제28권2호
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• pp.449-471
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• 2023

In this paper, we study a linear system of homogeneous commensurate /incommensurate fractional-order differential equations by developing a new semi-analytical scheme. In particular, by decoupling the system into two fractional-order differential equations, so that the first equation of order (δ + γ), while the second equation depends on the solution for the first equation, we have solved the under consideration system, where 0 < δ, γ ≤ 1. With the help of using the Adomian decomposition method (ADM), we obtain the general solution. The efficiency of this method is verified by solving several numerical examples.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2004년도 춘계공동학술대회 논문집
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• pp.620-623
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• 2004

Conventionally injection molds & dies are manufactured through an order-oriented manner. This brings unexpected orders into the shop floor such as hot order, re-work, and new types of mold & dies. Thus, there needs appropriate resource assignment plans considering the available times of machines and workers. Further, a scheduling system is required that can create work schedules periodically or by customers' requests. Yet, in small & medium sized mold & die makers, production schedules usually depend on the shop floor workers' experience and their manual preparation. Hence, developed in this study is a scheduling management system (SMS) based on order release and review (ORR) in small and medium sized mold & die companies. The proposed SMS considers delivery dates as well as flexible work schedules, so as to meet frequent changes of customers' order. The system can provide effective resource assigning and work scheduling plans, securing standard data associated with shop floors. Furthermore, the system pursues economical schedules for companies' needs, equipped with an available to promise (ATP) function that can effectively accommodate the changes of production plans.

• 한국광학회지
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• 제14권1호
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• pp.72-79
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• 2003

본 논문에서는 고차 편광모드분산(PMD: polarization-mode dispersion)을 효과적으로 보상하기 위한 방법으로, DOP (degree of polarization)를 1차 PMD 보상을 위한 피드백 신호와 고차 PMD 보상을 위한 feed forward 신호로 사용하는 알고리즘을 제안하였다. 1차 보상이 끝난 후의 DOP값이 남아있는 고차 PMD의 정도를 나타내는 척도로써 인식하여 고차 PMD를 보상하는 시스템이 되겠다. 이러한 시스템은 고차 보상기의 자유도를 1차 보상기의 자유도로 제한하기 때문에 안정적이고 비교적 간단하게 구성할 수 있다는 장점이 있다. 제안된 알고리즘의 성능을 분석하기 위하여 10Gbps NRZ시스템의 전송 모의 실험을 수행하였으며, 그 결과 시스템 다운 시간인 outage probability가 약 세 배 가량 감소되는 것을 확인하였다.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.287-292
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• 2005

In this paper, a state steering strategy using digital control method for chained system is presented. The chained system can be derived from the velocity or acceleration constraints that cannot be integrable. Especially, the chained system derived from an acceleration constraints is called the high order chained system. Such a system classified as a nonholonomic systems and cannot be controlled to its equilibrium points by continuous and time-invariant controller. Therefore discontinuous and time varying controller should be applied to control nonholonomic system. Using variable transformation, two sub system can be obtained from the chained or high order chained system. Deadbeat control and iterative state steering methods are proposed to control the systems that obtained from the variable transformation. Simulation results are given to show the effectiveness of the proposed control scheme.