• Korean Management Science Review
• /
• v.29 no.1
• /
• pp.1-14
• /
• 2012

The goal of the multi-reservoir operation planning is to provide an optimal release plan that maximize the reservoir storage and hydropower generation while minimizing the spillages. However, the reservoir operation is difficult due to the uncertainty associated with inflows. In order to consider the uncertain inflows in the reservoir operating problem, we present a Stochastic Dynamic Programming (SDP) model based on the markov decision process (MDP). The objective of the model is to maximize the expected value of the system performance that is the weighted sum of all expected objective values. With the SDP model, multi-reservoir operating rule can be derived, and it also generates the steady state probabilities of reservoir storage and inflow as output. We applied the model to the Geum-river basin in Korea and could generate a multi-reservoir monthly operating plan that can consider the uncertainty of inflow.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 1999.02a
• /
• pp.194-197
• /
• 1999

Thermodynamic cycle analysis has been performed to maximize the liquid amount for two hydrogen liquefaction systems using two-stage GM(Gifford-McMahon) refrigerator. the optimal operating conditions have been analytically sought with real properties of normal hydrogen for the two-stage GM direct contact system and the two-stage GM precooled L-H (Linde-Hampson) system. In the precooled system, there existed optimal values for compressed mass flow and compressed pressure to maximize the liquefied mass. It was recommended to use a cryocooler, which had a large precooling capacity between 70 and 100K.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.7A
• /
• pp.660-668
• /
• 2010

In energy resource constrained networks, the network lifetime can be enhanced by optimally allocating energy resource among users based on the available channel state information and the residual energy information at each node. In this paper, we propose the relay selection scheme and power allocation scheme to maximize the network lifetime in wireless relay networks with capacity constraint. The computer simulation results show that the proposed scheme increase the network lifetime in comparison to the conventional schemes.

• Proceedings of the KIEE Conference
• /
• 1993.11a
• /
• pp.56-58
• /
• 1993

This report describes the high speed DC motor (8,000 rpm) that we have designed, manufactured and tested. DC motor is the best drive system in electric-mechanical energy conversion. The design concept for high speed and high energy density to DC motor is to maximize Ampere-conductor in armature and to maximize flux density in armature teeth, armature core, pole, yoke using flux path.

• Proceedings of the IEEK Conference
• /
• 2008.06a
• /
• pp.474-475
• /
• 2008

Portable device is powered by the battery. To use portable devices longer time without replacing the battery, you should maximize the lifetime of the battery. If you use efficient DC-DC converter, You can maximize the lifetime of the battery.

• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.1332-1336
• /
• 2003

An experimental method is presented to maximize the replication quality of UV-molded micro-optical components. It is important to maximize the replication quality, because one can obtain the replicated micro-optical components with desired properties by accurate control of the shape. In the present study, a simple technique to avoid micro-air bubbles was first suggested. The effects of the UV-curing dose and the compression pressure on the replication quality of UV-molded structure were examined experimentally. Finally, as a practical application of the process design method, microlens arrays with diameters between 8 ${\mu}m$ and 96 ${\mu}m$ were fabricated by the present method, and the replication quality and the optical properties of the replicated microlens were measured and analyzed.

• Advances in aircraft and spacecraft science
• /
• v.2 no.4
• /
• pp.469-482
• /
• 2015

This study has the aim to develop a numerical design regarding the position and the inner performances of a heat exchanger in a light helicopter. the problem was to find first of all the best position of the heat exchanger inside the engine vane in order to maximize the air flow rate capable to pass through the heat exchanger section. It is to be said that the only air contribution in the vane comes from the opening present in the roof under the main rotor. The design has been performed by means of the commercial code Fluent and using the well known grid generator ICEM CFD. Different positions are first investigated so to establish the best one. Subsequently, different areas of the opening on the roof have been considered in order to maximize even more the flow rate in the heat exchanger that was not sufficient based on the first guess of velocity, as aforementioned. At the end interesting design results are presented and discussed by contours of fields and values.

• Journal of Magnetics
• /
• v.6 no.1
• /
• pp.31-35
• /
• 2001

This paper describes the design method of a magnetic system to maximize the magnetic flux leakage (MFL) in a non-destructive testing (NDT) system. The defect signals in a MFL type NDT system mainly depend on the change of the magnetic leakage flux in the region of a defect. The characteristics of the B-H curves are analysed and a design method to define the operating point on B-H curves for maximum leakage is performed. The computed MFL signal by a nonlinear finite element method is verified by measurement using Hall sensors mounted on the 6 legs PIG, the traveling detector unit in gas pipe, in an 8 inch test tube with defects. The rhombic defects could be successfully identified from the defect signals.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.2 no.2
• /
• pp.85-98
• /
• 1990

Method of optimum design of a compact sensible plate-fin heat exchanger for the heat recovery of exhaust gas from the air conditioning space was developed in consideration of the econamics of investment cost and profit according to the installation of heat exchanges. In the counterflow heat exchanger, the frontal area was fixed and the length of heat exchanger was optimized in order to maximize the net gain according to the setting of the heat exchanger. In the cross flow heat exchanger, the size of the exchanger was also optimized to maximize the net gain.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.2 no.2
• /
• pp.115-124
• /
• 1979

The purpose of this study is theoretical research on risk. The research is focused on systematic risk. Chapter I is objective of this study, Chapter II includes definition and measurement of risk. Chapter III introduces attitudes toward risk and classification of risk. Chapter IV discusses Portfolio theory, Capital market line and Shape and Lintner model The objective of firm is assumed to maximize its value. In a world of uncertainty, value is not determined by earnings alone, the degree of risk involved with the streams of earnings. Financial manager has to consider the risk in order to maximize the value of firm. Total risk can be classifier into two parts : Systematicrisk and unststematic risk by Sharpe. Systematic risk is important because investors can't diversify it. Blume and Jensen measured f and they testified that the f is stationary over the time For further study, Korean stock mark has to take emperical study about $\beta$ and its stationarity.