• 대한산업공학회지
• /
• 제23권3호
• /
• pp.501-514
• /
• 1997

Manufacturing is fast entering a new age of industrial excellence that is being called "Agile Manufacturing." The goal of Agile Manufacturing is to link customers, suppliers, and the manufacturing system into a super-efficient confederation to produce a variety of products quickly and at a low cost. In order to improve the quality of the study of production input control(PIC) in a job shop manufacturing system by reducing the significant gap between research models and models of actual manufacturing systems, the previous line of research on PICs in a job shop manufacturing system is extended by integrating customers and suppliers with the manufacturing system. Then, a set of measures is developed to evaluate PICs, measures that reflect concerns of customers and suppliers as well as concerns of the manufacturer. Also, a weighted overall measure (with various cases to represent different possible weights of manufacturer's emphasis on the performance measures) is used to synthesize all the performance measures. Then, for each case, various existing PICs are evaluated in combination with various priority dispatching rules(PDRs).

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2011년도 제42회 하계학술대회
• /
• pp.374-375
• /
• 2011

This paper presents a method to determine parameters of BTB (back-to-back) converters in terms of the enhancement of interface flow margins. Interface flow margin is by definition a measure of how much active power can be transferred from the external areas to the study area with the fixed load demand, and it is mainly constrained by system voltage stability. BTB converters are controllable equipments with the active power flow through them, and its DC link in fact can divide the AC systems at the location and hence can reduce the fault current level. This paper first cals margin sensitivities at the nose point of F-V curves and formulates an optimization problem to update the BTB parameters to improve the margins. This procedure is repeated performed until the required margin enhancement is achieved.

• 산업기술연구
• /
• 제21권A호
• /
• pp.59-64
• /
• 2001

This paper analyzes the performance of the several types of ACL(Asynchronous ConnectionLess) packets used in Bluetooth according to a BER(Bit Error Rate) and a packet length and proposes an optimal packet type and an optimal size of the packet being able to be used under the given BER. This paper proposes how to obtain the optimal packet type and the optimal size of the packet maximizing the performance measure under the given BER. In addition, this paper shows that the optimal type and size of the packet maximizing the throughput are different from those maximizing the mean transmission time. This occurs because the Bluetooth uses not only one type of packet but also various types of packets.

• 제어로봇시스템학회논문지
• /
• 제2권3호
• /
• pp.220-228
• /
• 1996

This paper presents a extended stochastic Petri net (ESPN) model for CTN(Circulated Token with No duration) service in the data link layer of IEC/ISA fieldbus. It is assumed that a station on the fieldbus has a specified minimum token holding time, a finite capacity buffer, and one transmitter queue with the highest priority. The mean transmission (or service) time at a station and the mean token rotation time for the symmetric fieldbus system atr derived using the presented SPN model and the moment generating function. These performance measures are represented in terms of the minimum token holding time, the number of stations, the arrival rate of messages, and the mean length of messages. The presented performance measure are validated by computer simulations.

• 센서학회지
• /
• 제17권1호
• /
• pp.23-28
• /
• 2008

In order to measure bio-signals, it is desirable to build a fully implantable system which connects directly to neural pathways or body tissue. A design scheme for fully implementable measurement system is proposed in this paper. Consisting of an implanted module and an external system, the proposed scheme delivers power and data between the two modules. The external module sends power via inductive link using a simple H-bridge type oscillator. Also, the implanted module sends measured data to the external system utilizing R/F communication technique at a frequency of ISM band. A stable communication and operation is achieved as the two types of channels are separated. Implemented in a compact size enough to be implanted in human body, the system exhibits good performance in experimental studies.

• Journal of electromagnetic engineering and science
• /
• 제6권4호
• /
• pp.222-228
• /
• 2006

In this paper, the performance of a multiuser diversity system combined with a multi-element transmit antenna system is analyzed under the assumption of independent Rayleigh fading. A measure of system .level performance is an average channel capacity as a function of the number of users and antennas. Average channel capacity is obtained from the instantaneous signal-to-noise ratio(SNR) distribution combined by both transmit diversity(TD) at each link and multiuser diversity at system level. Numerical results show that closed-loop antenna techniques provide an additional gain with multiuser diversity system due to array gain, even though space diversity gain reduces multiuser diversity gain. On the other hand, the space-time block coding(STBC) that provides full order space diversity gain only has a destructive influence on multiuser diversity.

• Management Science and Financial Engineering
• /
• 제12권2호
• /
• pp.19-35
• /
• 2006

We use the hierarchical Bayesian approach to describe the transition probabilities of a binary nonhomogeneous Markov chain. The Markov chain is used for describing the transition behavior of emotionally disturbed children in a treatment program. The effects of covariates on transition probabilities are assessed using a logit link function. To describe the time evolution of transition probabilities, we consider two modeling strategies. The first strategy is based on the concept of exchangeabiligy, whereas the second one is based on a first order Markov property. The deviance information criterion (DIC) measure is used to compare models with two different time dependent structures. The inferences are made using the Markov chain Monte Carlo technique. The developed methodology is applied to some real data.

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2005년도 춘계학술발표대회
• /
• pp.1397-1400
• /
• 2005

Multiprotocol Label Switching is an initiating IETF that integrated Layer2 information network links(bandwidth, latency, utilization) to Layer 3(IP) with a particular autonomous system(or ISP) in order to simplify and improve IP-packet exchange. MPLS gives network operators a grate deal of flexibility to divert and route traffic around link failures, congestion, and bottlenecks. The MPLS has advantages that will be able to solve existing problem of Network that ISP have had IP, QoS, Gigabit forwarding and traffic engineering. The purpose of this study is to measure Access-list and the capacities of PE Router that would operate as MPLS. Many ISP using MPLS service to handle high-speed internet traffic with apply to firewall in future.

• 한국유기농업학회지
• /
• 제17권3호
• /
• pp.327-345
• /
• 2009

Environment-friendly agricultural products market has been experiencing various change through the quantitative growth in Korea. The food safety is considered seriously and the interest of the consumer is increasing about environment-friendly agricultural products and organic agricultural products. Environment-friendly agricultural products is encouraged in the link of the counter-measure which follows in the market opening. This research aims at making shorter the distance between the productive person and the consumer and to improve the income for organic farm and the price competitiveness for Environment-friendly agricultural products through the present condition analysis for organic produce's production, distribution and consumption market. To solve the problems above, the development of strategies for the establishment of distribution system for the organic produce's stable supply and the improvement of price competitiveness, the establishment of the cooperating system on the produce's demand and supply, the improvement of consumer's reliability by reinforcement with connectivity and transparency of the process, and the vitalization of regional economy and the exchange of rural and city area are needed.

• 오토저널
• /
• 제12권6호
• /
• pp.60-66
• /
• 1990

In order to measure the piston surface temperature and heat flux, autors have developed the measuring system with an instantaneous temperature probe. Such the instantaneous temperature probes were embodied into the top of piston for measurement and L-link system, designed to fit the test engine, extracts the thermocouple wires from the piston outside of engine employing a mechanical linkage. Then the instantaneous surface temperature was measured to calculate the heat flux flowing into the top surface of piston in a spark ignition engine. As a result, the following phenomena have been obtained through the study. 1) It is found that the time response and durability of temperature probe with a thin film thickness 10um and mechanical linkage with thermocouple wire extraction is sufficient at this experiment. 2) For the quantitative effect of variation in engine speed, the temperature swing and heat flux on the top of piston increase with increasing the engine speed. 3) It is proved that the temperature swing and heat flux decrease with distance from spark plug.