• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.605-606
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• 2006

Voltage Controlled Oscillator(VCO) plays an important role in today's communication systems. Especially, a Clock Generator(CG) in phase-locked loop(PLL) is usually realized by the VCO. This paper proposes a new VCO with a controllable duty cycle buffer, that can be adopted in low-power high-speed communication systems. Delay cell of the VCO is implemented with gilbert cell. Frequency dynamic range of the VCO is in the range of approximately $50MHz{\sim}500MHz$. Parameters with N-well CMOS 0.18-um process with 1.8V supply voltage was used for the simulations.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.6 s.171
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• pp.183-191
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• 2005

Axiomatic design offers a scientific base for design in an efficient way. It is well known that it has two axioms: the Independence Axiom and the Information Axiom. Many applications of the Independence Axiom have been published, however, the Information Axiom has been mainly applied to IFR (functional requirement) - 1DP (design parameter) problems except fer a few case studies. This research presents various methods for calculation of information content. Generally, the information content is evaluated by the probability of success. The probability of success is calculated in two ranges: the FR range and the DP range. In the FR range, the graphical method is utilized with uniform distribution of the DP. In the FP range, the integration method is employed. It is noted that any distribution function of the DP can be accommodated in the integration method. The developed method can be applied to a decoupled design with multiple FRs and DPs. The developed method is extended to a coupled design and a design with a hierarchical structure of axiomatic design.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.11
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• pp.2521-2530
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• 1997

In this paepr, we present a video-on-demand (VOD) system design model that address and integrates a number of inter-related issues. Then with analysis and performance evaluation, we investigate various aspects of disk and buffer managements in the given model. Based on the analysis results, we suggest that a distributed buffering scheme with intermediate buffers may te useful to transform bursty disk accesses into a continuous stream for for glitch-free performance of VOD systems. Also, through simulation, we illustrate that massive multimedia information storage design techniques such as prefetching, clustered striping, and real-time disk scheduling integrated with the distributed buffering mechanism may enhance end-to-end real-time performance of VOD systems under wide-area networks.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.2005-2009
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• 2009

Urban transit consists of signaling system, railway systems, power facilities systems, information and communication system and the other complicated facilities. There are many new technologies to analysis the requirement of for information and communication system. The more system is complicate, the more system design error occur frequently in development of information and communication system. Now, we need to reduce the error by analysis the behavior of the requirements of it. Thus in this paper, we suggest the way to analysis the behavior of the requirements by using the computer aided design tools.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.552-557
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• 2008

This paper introduces to schematic design for Korea Institute of Toxicology Second Campus at Jeong-eup and provides fundamental information and data in order to design this laboratory facility to meet the criteria of G.L.P(Good Laboratory Practice), AAALAC(Association for Assessment and Accreditation of Laboratory Animal Care) and so on. This paper especially focus on design criteria, HVAC(Heating Ventilating and Air Conditioning) equipment and systems, plumbing equipment and systems, maintenance of equipment and systems and energy saving system of this laboratory facility.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2258-2263
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• 2003

This paper presents the design and development of an optimal fuzzy logic controller (FLC) for a laser tracking system. An optimal intelligent fuzzy logic controller was founded on integral criterion of the fuzzy models and three-dimensional fuzzy control. Research had been also concentrated on the methods for multivariable fuzzy models for the purposes of real-time process. Simulation results have shown remarkable tracking performance of this fuzzy PID controller.

• Journal of Information Processing Systems
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• v.15 no.3
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• pp.570-592
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• 2019

The Event-B design pattern is an excellent way to quickly develop a formal model of the system. Researchers have proposed a number of Event-B design patterns, but they all lack formal behavior semantics. This makes the analysis, verification, and simulation of the behavior of the Event-B model very difficult, especially for the control-intensive systems. In this paper, we propose a novel method to transform the Event-B synchronous control flow design pattern into the labeled transition system (LTS) behavior model. Then we map the design pattern instantiation process of Event-B to the instantiation process of LTS model and get the LTS behavior semantic model of Event-B model of a multi-level complex control system. Finally, we verify the linear temporal logic behavior properties of the LTS model. The experimental results show that the analysis and simulation of system behavior become easier and the verification of the behavior properties of the system become convenient after the Event-B model is converted to the LTS model.

• Asia pacific journal of information systems
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• v.12 no.3
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• pp.21-43
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• 2002

This paper examines internet shopping mall members' relationship quality and its antecedents variables. For this purpose, five types of membership customers' perceived variables, including convenience, product assortment, product information, shopping mall design, and service quality are proposed to affect customer satisfaction and consequently relationship quality. This study, which used data from customers of membership internet shopping malls, showed satisfactory data-fit to the proposed model and except product information hypothesis, supported all of research hypotheses. Also four types of membership customers' perceived variables(convenience, product assortment, shopping mall design, and service quality) take significant effect on customer satisfaction, and the satisfaction in turn have influence on relationship quality.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.11
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• pp.4331-4346
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• 2015

The femtocell network, which is designed for low power transmission and consists of consumer installed small base stations, coexists with macrocells to exploit spatial reuse gain. For its realization, cross-tier interference mitigation is an important issue. To solve this problem, we propose a joint access and power control scheme that requires limited information exchange between the femto and macro networks. Our objective is to maximize the network throughput while satisfying each user's quality of service (QoS) requirement. To accomplish this, we first introduce two distributed interference detection schemes, i.e., the femto base station and macro user equipment based schemes. Then, the proposed scheme dynamically adjusts the transmission power and makes a decision on the access mode of each femto base station. Through extensive simulations, we show that the proposed scheme outperforms earlier works in terms of the throughput and outage probability.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.3
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• pp.458-465
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• 2008

In this paper, we propose a non-fragile guaranteed cost controller design method for uncertain linear systems with constant delyas in state. The norm bounded and time-varying uncertainties are subjected to system and controller design matrices. A quadratic cost function is considered as the performance measure for the system. Based on the Lyapunov method, an LMI(Linear Matrix Inequality) optimization problem is established to design the controller which uses information of delayed state and minimizes the upper bound of the quadratic cost function for all admissible system uncertainties and controller gain variations. Numerical examples show the effectiveness of the proposed method.