• Communications for Statistical Applications and Methods
• /
• v.28 no.6
• /
• pp.643-653
• /
• 2021

Few studies are found in literature on estimation of population quantiles using the method of ranked set sampling (RSS). The optimal RSS strategy is to select observations with at most two fixed rank order statistics from different ranked sets. In this paper, a near optimal unbalanced RSS model for estimating p^th(0 < p < 1) population quantile is proposed. Main advantage of this model is to use each rank order statistics and is distributionfree. The asymptotic relative efficiency (ARE) for balanced RSS, unbalanced optimal and proposed near-optimal methods are computed for different values of p. We also compared these AREs with respect to simple random sampling. The results show that proposed unbalanced RSS performs uniformly better than balanced RSS for all set sizes and is very close to the optimal RSS for large set sizes. For the practical utility, the near optimal unbalanced RSS is recommended for estimating the quantiles.

• Korean Management Science Review
• /
• v.14 no.1
• /
• pp.53-66
• /
• 1997

Generally, the standard sizes of military combat fatigues should be determined by considering the coverage rate in order to minimize the military personnel who can't put on the ready made military combat fatigues. The coverage rate should be increased by the longer interval of the standard size but the satisfactory rate will be decreased due to the longer interval of size. This study develops a method selecting optimal standard sizes of the military combat fatigues in order to maximize the satisfactory rate that insures the coverage rate to meet a given level for ready made military combat fatigues. This method selects candidate standard sizes at second and finally, establishes a 0-1 inter programming model. The result shows that the method increases both coverage and satisfactory rate more than those of the previous method.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.14 no.1
• /
• pp.53-53
• /
• 1989

Generally, the standard sizes of military combat fatigues should be determined by considering the coverage rate in order to minimize the military personnel who can't put on the ready made military combat fatigues. The coverage rate should be increased by the longer interval of the standard size but the satisfactory rate will be decreased due to the longer interval of size. This study develops a method selecting optimal standard sizes of the military combat fatigues in order to maximize the satisfactory rate that insures the coverage rate to meet a given level for ready made military combat fatigues. This method selects candidate standard sizes at second and finally, establishes a 0-1 integer programming model. The result shows that the method increases both coverage and satisfactory rate more than those of the previous method.

• Journal of information and communication convergence engineering
• /
• v.10 no.3
• /
• pp.242-247
• /
• 2012

In the determination of suitable frame sizes associated with dynamic framed slotted Aloha used in radio frequency identification tag identification processes, the widely imposed constraint $L=2^Q$ often yields inappropriate values deviating far from the optimal values, while a straightforward use of the estimated optimal frame sizes causes frequent restarts of read procedures, both resulting in long identification delays. Taking a trade-off, in this paper, we propose a new method for determining effective frame sizes where the effective frame size changes in a multiple of a predetermined step size, namely ${\Delta}$. Through computer simulations, we show that the proposed scheme works fairly well in terms of identification delay.

• Journal of the Korean Data and Information Science Society
• /
• v.14 no.1
• /
• pp.55-65
• /
• 2003

In this study, we systemize the theoretical validity for applying unrelated question model to three-stage cluster sampling method and derive the estimate and it's variance of sensitive parameter. We derive the minimum variance form under the optimal values of the subsample sizes when the cost are fixed. Under the some given precision, we obtain the optimal values of the subsample sizes and derive the minimum cost form by using them.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.29 no.8 s.145
• /
• pp.1102-1113
• /
• 2005

The propose of this study is to develop the optimal sizing system of ready-to-wear f3r elementary school girls using a newly invented statistical technique. The body measurements was classified by the method that equalizes the distribution of the subjects using the probability density function, to theoretically systemize a method to determine a size range of ready-to-wear for elementary school girls between 6 to 12 years old. The statistical method were 1) The total of 11 height groups, which size interval from one another is 6 cm that is an average height gap between each age. 2) In order to determine an approximate figure (m ${\times}$ n) to establish the appropriate sizes far each height group that fit to the combinations of bust and hip girth, which based on their means and standard deviations on the probability density curve to produce the standard normal distribution. 3) m and n were aligned by 4cm -the grading increments used for patterns making- and determined the size ranges by confirming the approximate figures of m and n. 4) The representative values were determined by an area ratio calculated by dividing the area determined from the range of bust and hip girth with the representative value. Considering the characteristics of subjects' distribution, the area ratios was used. 5) Weight was calculated by seeking a growth exponent for each age and multiplying it by the number of girls that fit to each size range. As sections that show the highest weight are more likely sought by the consumers, these sections were determined as the optimal size standards. 6) This optimal sizing system consists of sizes determined by the optimal size standards and its sizes are marked with height, bust and hip girth.

• Journal of the Korean Statistical Society
• /
• v.15 no.2
• /
• pp.127-130
• /
• 1986

Constantine(1981) extended the results of Takeuchi(1961) by adding some new blocks to certain known E-optimal block design. But they are confined to equal blocksize designs. In this paper we agin generalize them to different blocksize case. By augmenting some known E-optimal block designs having blocks of equalsize with blocks of different sizes, additional E-optimal block designs are obtained.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.31A no.10
• /
• pp.1-9
• /
• 1994

In this paper, we have studied optimal FCL(Frequently Called List) table sizes in a grid topology circuit-switched network including wireless subscribers. The FCL table gives the position information of a destination subscriber for a call. When the call is generated in a node, this call is routed by the referenced position information of the destination subscriber in FCL table. In this paper, we have proposed an efficient routing algorithm, mixed FSR(Flood Search Routing) and DAR(Dynamic Adaptive Routing), considering moving wireless subscribers. Also, we have simulated hit ratio and incorrect ratio as performance parameters, consequently proposed the object function composed of table search time, hit ratio, incorrect ratio, FSR time and DAR time, and derived the optimal FCL table size by using it.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1994.10a
• /
• pp.217-222
• /
• 1994

This paper describes the determination of optimal initial billet size for axisymmetric cold forging products using neural networks. The determination of optimal initial billet size is very important in forging design and forming sequence design, because the result of such designs and forming load can be different by variable initial billet sizes. The forming difficulty has been defined as the degree of difficulty in forming by 3 process ' forward extrusion, backward extrusion and upsetting. By neural networks a forming difficulty can be determined with the ratio of shape and forming process. From the graph of maximum, minimum, and average forming difficulties by variable billet sizes, the optimal billet size can be determined. The initial billets of a solid part and a hollow part whichwas determined by this study are compared with the sequence drawing generated by the one of forming sequence design system.

• Transactions of Materials Processing
• /
• v.8 no.5
• /
• pp.437-448
• /
• 1999

The reheating of the billet in the semi-solid state as quickly and homogeneously as possible is one of the most imposrtant parts. To obtain a fine globular microstructure in cross section of billet, the optimal design of the induction coil for variation of alloys and specimen sizes is necessary. For the thixo-forging process the construction of the reheating data base is very important, because the reheating conditions are different for variation of SSM and billet sizes. So in this study, the optimal coil design of A356 (ALTHIX) and Aι2024 with d×ι=60×90 (mm) to obtain the globular microstructure is theoretically proposed. The suitability of an optimal coil design will be demonstrated by reheating experiments. Finally, the thixoformability of an arbitrarily shaped product is evaluated by its forming variables. The defects and mechanical properties are also investigated.