• Journal of applied mathematics & informatics
• /
• v.31 no.5_6
• /
• pp.869-876
• /
• 2013

The design of large family size with the optimal cross-correlation property is important in spread spectrum and code division multiple access communication systems. In this paper we present the sequences with the decimation $d=2{\cdot}2^m-1$, calculate the cross-correlation spectrum for $0{\leq}t{\leq}2^n-2$ and count the number of the value $2^m-1$ occurring for $0{\leq}{\tau}2^n-2$. The sequences have the optimal cross-correlation property. The work on this paper can make it easier to count the number of the whole value occurring for $0{\leq}{\tau}2^n-2$.

• Journal of Korean Society for Quality Management
• /
• v.26 no.3
• /
• pp.141-149
• /
• 1998

It is of great practical interest to decide when to stop testing a software system in the development phase and transfer it to the user. This decision problemcalled an optimal software release one is discussed to specify the a, pp.opriate release time. In almost all studies, the software reliability models used are nonphomogenous Poisson process(NHPP) model with bounded mean value function. HNPP models with unbounded mean value function are more suitable in practice because of the possibility of introducing new faults when correcting or modifying the software. We discuss optimal software release policies which minimize a total average software cost under the constraint of satisfying a software reliability requirement. A numerical example illustrates the results.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.12 no.2
• /
• pp.42-50
• /
• 1987

This objective of this paper is to develop an efficient method with small memory requirement for a feed-mixing problem on a micro computer. First this method uses the decomposition principle to reduce the memory requirement. Next, the decomposition principle is modified to fit the problem. Further four different variations in solving subproblems are designed in order to improve efficiency of the principle. According to the test with respect to the processing time, the best variation is such that the dual simplex method is used, and the optimal basis of a previous subproblem is used as an initial basis, and the master problem is (M +1) dimensional. In general, the convergence of solution becomes slower near the optimal value. This paper introduces a termination criterion for a sufficiently good solution. According to the test, 5%-tolerence is acceptable with respect to the relation between the processing time and optimal value.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.32 no.1
• /
• pp.147-160
• /
• 2007

In this paper, the optimal decision making strategy for resource management is viewed in terms of a combined strategy of planting and producing time. A model which can be used to determine the optimal management strategy is developed, and focuses on how to design the operation of a Markov chain so as to optimize its performance. This study estimated a dynamic stochastic model to compare alternative production style and used the net present value of returns to evaluate the scenarios. The managers in this study may be able to increase economic returns by delaying produce in order to market larder, more valuable commodities.

• Proceedings of the KIEE Conference
• /
• 2000.07a
• /
• pp.265-267
• /
• 2000

A method to compute the reactive powers of the added buses by the decoupled UPFC model for the optimal voltage profile is presented, by which the voltage magnitudes of PQ buses can get closer to the reference value(usually one p.u.). The performance index for assessing how much the voltage magnitude is closer to the reference value is defined as the squared sum of the present voltage minus the reference voltage multiplied by the weighting number associated with the relative importance of the buses. Numerical example in a 10-unit 39-bus power system with 2 UPFC's shows that the performance index can be very much reduced by operating multi UPFC's with the reactive powers for the optimal voltage profile proposed in this paper.

• Korean Journal of Veterinary Service
• /
• v.21 no.2
• /
• pp.107-115
• /
• 1998

In order to establish a rapid, sensitive and specific diagnostic method for detection of antibody to Brucella abortus, a enzyme-linked immunosorbent assay(ELISA) was adapted. The diagnostic efficacy of the established ELISA was compared with that of the standard tube agglutination test for B abortus. 1. It was found that the optimal concentration of antigen for this ELISA was 5$\mu\textrm{g}$/ml, the optimal dilution of conjugate was 1 : 2000, and the optimal dilution of serum was 1 : 200, respectively. 2. Cut off value in this ELISA was 1,102 that was determined by mean absorbance(at 492nm) of tube agglutination test negative serum added with the triple value of the standared devation. 3. The relationship between the tube agglutination test and ELISA was showen high corresponding rate with sensitivity(96.3%) and specificity(98.1%). 4. The efficacy of the ELISA for detection of B abortus antibody was compared with tube agglutination test In brucellosis outbreak farm. The sensivity of ELSIA was higher than tube agglutination test.

• East Asian mathematical journal
• /
• v.24 no.1
• /
• pp.45-55
• /
• 2008

We consider an M/G/1 queue with $P^M_{\lambda}$-service policy, which is a two-stage service policy. The server starts to serve with rate 1 if a job arrives to the sever in idle state. If the workload of the system upcrosses $\lambda$, then the service rate is changed to M and this rate continues until the system is empty. It costs to change the service rate to M and maintaining the rate. When the expectation of the stationary workload is supposed to be less than a given value, we derive the optimal value of M.

• 제어로봇시스템학회:학술대회논문집
• /
• 1990.10b
• /
• pp.1150-1155
• /
• 1990

This paper proposes an optimal redundancy resolution of a kinematically redundant manipulator while considering homotopy classes. The necessary condition derived by minimizing an integral cost criterion results in a second-order differential equation. Also boundary conditions as well as the necessary condition are required to uniquely specify the solution. In the case of a cyclic task, we reformulate the periodic boundary value problem as a two point boundary value problem to find an initial joint velocity as many dimensions as the degrees of redundancy for given initial configuration. Initial conditions which provide desirable solutions are obtained by using the basis of the null projection operator. Finally, we show that the method can be used as a topological lifting method of nonhomotopic extremal solutions and also show the optimal solution with considering the manipulator dynamics.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.20 no.2
• /
• pp.174-179
• /
• 2011

This paper focuses on the optimal step-over value for magnetic tool path. Since magnetic flux density is changed according to distance from center of magnetic tool. Enhanced surface roughness is also different according to change of radius. Therefore, to get a identical surface roughness on workpiece, it is necessary to find optimal tool path including step-over. In this study, response surface models for surface roughness according to change of radiuses were developed, and then optimal enhanced surface roughness for each radius was selected using genetic algorithm and simulated annealing to investigate relation between radius and surface roughness. As a result, it found that step-over value of 6.6mm is suitable for MAP of magnesium alloy.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.05a
• /
• pp.645-650
• /
• 2002

In this paper, new concept, low noise axial fan was developed. The fan was designed to operate at high-pressure condition inside the refrigerator. This fan - we call it Alpha fan - has small turbo blades at trailing edge of axial fan. These turbo blades make alpha fan operate at high pressure and low noise condition. In order to find out the optimal value of design parameters, 6-sigma method was used. The design parameters are ratio between inner and outer diameter, Height, Install angle and Install position of turbo blade. Optimal value of turbo blade was found out and the noise generated from this fan is reduced about 3dB(A).