• Journal of Biomedical Engineering Research
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• v.3 no.1
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• pp.9-16
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• 1982

Removal of urea and vitamin B12 was simulated using two pool models with closed loop dialysis, open loop dialysis, and hemodiafiltrations with predilution and postdilulion. It was found that urea removal was limited by dialyzer clearance, however B12 removal was limited both by the resistance between ECF and ICF and by dialyzer clearance. Open loop dialysis was better than closed loop dialysis in terms of dialysate requirement and removal efficiency. Residual renal function plays an important role in removing vitamin B12. Dialysis frequency more than twice/wide does not have great effect on removal efficiency, but has the effect of reducing the difference between maximum and minimum cancentrations during dialysis period.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.291-294
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• 2003

The Water resources utilization pattern of Jangsung reservoir was studied. The observed precipitation and existing reservoir operation data such as irrigation amount, reservoir storage, river maintenance requirement, flood control discharge were collected for ten years period and analyzed. Major findings of this study are as follows: The observed average, minimum, maximum annual precipitation were 905.1mm, 1,977.3mm, 1,554.3mm during study period, respectively. The average annual irrigation amount was 554.5mm, irrigation amount of drought years of '92 and '94 was 604.6mm, 679.2mm, respectively. However, irrigation amount of extended drought year '95 was 384.9mm. It showed that supplying capacity of Jangsung reservoir was limited when consecutive 2 year drought occurred. The main water resources usage of Jangsung reservoir was irrigation, but flood control discharge exceed irrigation amount exceptionally when high precipitation occurred. The reservoir operation record revealed that discharge for river maintenance was delivered even drought years.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2108-2111
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• 2005

The mission life of a satellite determines the amount of fuel required on-board, while the total mass requirement limits the fuel to be loaded. Hence, for the design of thruster control loop, not only the satellite pointing accuracy but the saving of fuel is to be considered. In this paper, a two-step fuzzy controller is proposed for the thruster control loop to save fuel consumption. This approach combines requirements for pointing control accuracy with minimum fuel consumption into a fuzzy controller design. To demonstrate this approach, we have designed a fuzzy controller for the Sun point Mode of KOMPSAT-2. The performance of this fuzzy controller design is compared with that of PD controller used for KOMPSAT-2.

• IEMEK Journal of Embedded Systems and Applications
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• v.15 no.3
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• pp.111-118
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• 2020

We investigate the optimization problem of transmit power control and MMSE Receiver filter for multi access points environment. Previous work showed that increasing the number of access points decreases the transmit power consumption. Accordingly, transmit power control algorithm was developed in such a way that the transmit power is minimized, while each terminal meets Signal to Interference and Noise Ratio Requirement. In this work, we further reduce the transmit power consumption by optimizing the transmit power level and the MMSE receiver filter together. We showed that the proposed joint optimization algorithm satisfies the necessary and sufficient conditions to be standard interference function, which guarantees convergence and minimum transmit power consumption. We observed that the proposed algorithm outperforms the algorithm which only optimizes the transmit power.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.5
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• pp.1240-1255
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• 1996

This paper suggests power optimization technique in multi-level SCPC system as a method for efficient utilization of limited satellite power. The power optimization is realized by optimal assignment of satellite input carrier powers considering interference and noise generated in up-link and down-link. The Fletcher-Powell algorithm searching minimum(or maximum) point using gradient information is used to detemine the optimal input carrier powers. To apply Flectcher-Powell algorithm mathematical descriptions and their partial derivatives to interference and nose are presented. Because a target, which should be optimized, is satellite input carrier power, amplitude of each carrier group will be assumed to be an independent variable. The performance criterion for optimal power assignmentis classified into 4 categories with respect to CNR of destination receiver earth station to meet the requirement for various satellite link environment. Simulation results for two-level, four-level and six-level SCPC system are presented.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.242-247
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• 2003

An experimental study presents characteristics of combustion in a combustion chamber by port deactivation valve for economy and emissions standards. In order to use combustion properties data it is necessary to build some data base, which use cylinder pressure sensor, etc. Port deactivation valve has been developed to satisfy requirement of achieving sufficient swirl generation to improve the combustion. A feasibility and necessity of combustion pressure based cylinder spark timing control has been examined. So, this was obtained the Coefficient of Variation(COV) and the mass-burned(MFB). The characteristics of pressure ratio fraction is similar to that of mass-burned fraction. Using the results of the test, the effects of the combustion chamber can be improved combustion stability by port deactivation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.551-555
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• 1996

The continuing demand for quality products requires better understanding and improved control of the production process. And, in recent year requirements for flatness control in strip rolling have become increasinglysevere because of the control for flatness of cold rolled strip is essential for further down stream processing. Also a speeds of rolling mills to meet productivity requirements puts a demanding requirement on the control of flatness of rolled strip. The demands on a total flatness control system therefore are a measuring and indication system consisting of a measuring roll that is robust, accurate, reliable and require a minimum of maintenance. The critical prt of any control system is the quality of the information being provided by the measurement instrument or device. It is therfore of utmost importance to have an accurate, repeatable and reliable measuring system. So, in this paper, The measuring roll for automatic flatness control system of contact type has been investigated.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.613-616
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• 2003

This paper describes the design and implementation of wideband 360$^{\circ}$ phase shifter by using I/Q vector method. One of four quadrants was selected by a switching operation and the desired phase value was obtained by varying attenuation level of attenuator located in I/Q path. The minimum phase RMS error of 3.6$^{\circ}$ and the maximum phase RMS error of 25.2$^{\circ}$ were measured over 6~180Hz frequency range. Those characteristics are good enough for the requirement of ECM radar equipment. The phase values can be adjusted by control module.

• ETRI Journal
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• v.20 no.2
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• pp.171-191
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• 1998

In this paper, we propose a new heuristic design algorithm for the virtual path (VP)-based ATM network with multiple traffic classes, in which QoS constraints associated with traffic class are taken into account. The minimum bandwidth of VP required to carry given amount of traffic is obtained by utilizing an equivalent bandwidth concept, and the route of each VP is placed so that the network cost is minimized while the QoS requirement is fulfilled To evaluate our design algorithm, we consider two kinds of traffic: voice traffic as low speed service and still picture traffic as high speed service. Through numerical examples, we demonstrate that our design method can achieve an efficient use of network resources, which results in providing a cost-effective VP-based ATM network.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.242-248
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• 1987

Recently, a quite large number of investigation is published on the subject of Flexible Manufacturing System which can cope with the volatile market demand and the variety of product. Minimum requirement of designing FMS is depicted and by investigating the communication system between the machine tool and the cell control computer, ana between the central computer and the cell control computer, when it is formed as a sub-system of an FEM, the software can be evolved to the control software of the total Flexible Manufacturing System. It is developed the communication system between the central computer and the cell control computer which is the basic structure of the control architecture of FMS under the concept of DNC (Direct Numerical Control). It is used CYBER 180-830 as the central computer, and GMC-1100 computer as the cell control computer, and the main basic program is developed and tested, thus forming a DNC system which can be used in educational environment.