• International conference on construction engineering and project management
• /
• 2011.02a
• /
• pp.534-541
• /
• 2011

Risk evaluation approaches for bidding on international construction projects are typically partitioned into three stages: country selection, project classification, and bid-cost evaluation. However, previous studies are frequently under attack in that they have several crucial limitations: 1) a dearth of studies about country selection risk tailored for the overseas construction market at a corporate level; 2) no consideration of uncertainties for input variable per se; 3) less probabilistic approaches in estimating a range of cost variance; and 4) less inclusion of covariance impacts. This study thus suggests a three-staged risk evaluation model to resolve these inherent problems. In the first stage, a country portfolio model that maximizes the expected construction market growth rate and profit rate while decreasing market uncertainty is formulated using multi-objective genetic analysis. Following this, probabilistic approaches for screening bad projects are suggested through applying various data mining methods such as discriminant logistic regression, neural network, C5.0, and support vector machine. For the last stage, the cost overrun prediction model is simulated for determining a reasonable bid cost, while considering non-parametric distribution, effects of systematic risks, and the firm's specific capability accrued in a given country. Through the three consecutive models, this study verifies that international construction risk can be allocated, reduced, and projected to some degree, thereby contributing to sustaining stable profits and revenues in both the short-term and the long-term perspective.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.17 no.11
• /
• pp.3204-3217
• /
• 2023

In this paper, the downlink of the multicast based spatial modulation systems is investigated. Specifically, physical layer multicasting is introduced to increase the number of access users and to improve the communication rate of the spatial modulation system in which only single radio frequency chain is activated in each transmission. To minimize the bit error rate (BER) of the multicast based spatial modulation system, a joint optimizing algorithm of antenna selection and multicast precoding is proposed. Firstly, the joint optimization is transformed into a mixed-integer non-linear program based on single-stage reformulation. Then, a novel iterative algorithm based on the idea of branch and bound is proposed to obtain the quasioptimal solution. Furthermore, in order to balance the performance and time complexity, a low-complexity deflation algorithm based on the successive convex approximation is proposed which can obtain a sub-optimal solution. Finally, numerical results are showed that the convergence of our proposed iterative algorithm is between 10 and 15 iterations and the signal-to-noise-ratio (SNR) of the iterative algorithm is 1-2dB lower than the exhaustive search based algorithm under the same BER accuracy conditions.

• Proceedings of the Korean Statistical Society Conference
• /
• 2002.05a
• /
• pp.1-5
• /
• 2002

We consider the problem of optimal bandwidth choice for nonparametric classification, based on kernel density estimators, where the problem of interest is distinguishing between two univariate distributions. When the densities intersect at a single point, optimal bandwidth choice depends on curvatures of the densities at that point. The problem of empirical bandwidth selection and classifying data in the tails of a distribution are also addressed.

• Journal of the Korean Data and Information Science Society
• /
• v.16 no.4
• /
• pp.861-870
• /
• 2005

The Bayesian model selection procedures for the shape parameter of gamma distribution are proposed in order to test that the failure rate of gamma distribution is constant, increasing or decreasing. The encompassing intrinsic Bayes factor by Beger and Pericchi (1996) based on Jeffreys prior for shape parameter is used to investigate the usefulness of the proposed Bayesian model selection procedures via both real data and pseudo data.

• Journal of the Korean Home Economics Association
• /
• v.36 no.11
• /
• pp.209-218
• /
• 1998

The purpose of this study was to conduct the review of female labor suply, and thus, to provide useful theoretical and empirical frameworks for future studies related to female labor supply. Based on the theory of the allocation of time, the process of individual labor supply was systematically reviewed. Participation Probit/Logit, Tobit, and Selection B;ias Corrected Regression were considered in estimating the function of female labor supply which modifies the selection bias. Based on the previous empirical results, wage rate, asset income, husband's income, the level of eduction, and child-related variables such as the presence of child and the number of children might be considered for the empirical specification of female labor supply.

• Korean Journal of Medicinal Crop Science
• /
• v.5 no.3
• /
• pp.191-195
• /
• 1997

This study was conducted to obtain the basic information on setting up selection procedure using seedling characteristics in Angelica gigas Nakai lines. Morphological characteristics of the seedlings including height, leaf and petiole length among lines tested showed difference significantly, meaning that earlier selection was possible. Bolting rate at maturity ranged from 0.6 to 74.6% and root yield did from 350 to 3,893kg/ha. Root yield was increased in the lines with below 5% bolting rate. Heritabilities of petiole length, seedling height and leaf length in seedling stage bolting rate and root yield were high, while those of leaf length, root diameter and root length were relatively low. Bolting rate at maturity was positively correlated with seedling height, leaf length, leaf width, petiole length and number of leaves. A highly significant negative correlation was showed between root yield and seedling height, leaf length and width, petiole length, number of leaves, root length or bolting rate. From the above results the selection markers were found to be height, leaf length and petiole length in seedling stage.

• Asian-Australasian Journal of Animal Sciences
• /
• v.30 no.2
• /
• pp.149-153
• /
• 2017

Objective: This study was to determine the relationship between estimated breeding value and phenotype information after farrowing when juvenile selection was made in candidate pigs without phenotype information. Methods: After collecting phenotypic and genomic information for the total number of piglets born by Landrace pigs, selection accuracy between genomic breeding value estimates using genomic information and breeding value estimates of best linear unbiased prediction (BLUP) using conventional pedigree information were compared. Results: Genetic standard deviation (${\sigma}_a$) for the total number of piglets born was 0.91. Since the total number of piglets born for candidate pigs was unknown, the accuracy of the breeding value estimated from pedigree information was 0.080. When genomic information was used, the accuracy of the breeding value was 0.216. Assuming that the replacement rate of sows per year is 100% and generation interval is 1 year, genetic gain per year is 0.346 head when genomic information is used. It is 0.128 when BLUP is used. Conclusion: Genetic gain estimated from single step best linear unbiased prediction (ssBLUP) method is by 2.7 times higher than that the one estimated from BLUP method, i.e., 270% more improvement in efficiency.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.10 no.2
• /
• pp.95-99
• /
• 2005

A breeding plan was carried out on four commercial strains of silkworm (Bombyx mori L.) 101, 102, 103 and 104 to improve some important traits. Genetic gain or response to selection $({\Delta}G)$, heritability of cocoon shell weight (CSW) and specific combining ability effects were estimated to determine the strains that can be improved. Strain 101 had lowest heritabitity, ${\Delta}G$ and viability. Strain 102 was acceptable in selection response but its viability was low. Therefore these two strains were not suitable for more selection. As a result, only lines 103 and 104 were chosen for further improvement. Intra population selection based on independent culling level method practiced from third to sixth generation for both productive and viability traits simultaneously. While CSW and CW had increasingly enhanced during primary generations, they went slightly up after third generation. According to negative genetic correlation, viability decreased during primary generations, but after third generation that paid attention to balanced development of both productive and viability traits, viability increased so that the pupation rate reached to $91\%$ in 103 and $97\%$ in 104 for last generation $(G_8)$.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.23 no.2
• /
• pp.198-209
• /
• 1999

This study reports the selection of dependent variables for momentum equations in general curvilinear coordinates. Catesian, covariant and contravariant velocity components were examined for the dependent variable. The focus of present study is confined to staggered grid system Each dependent variable selected for momentum equations are tested for several flow fields. Results show that the selection of Cartesian and covariant velocity components intrinsically can not satisfy mass conservation of control volume unless additional converting processes ore used. Also, Cartesian component can only be used for the flow field in which main-flow direction does not change significantly. Convergence rate for the selection of covariant velocity component decreases quickly as with the increase of non-orthogonality of grid system. But the selection of contravariant velocity component reduces the total mass residual of discretized equations rapidly to the limit of machine accuracy and the solutions are insensitive to the main-flow direction.

• The Research Journal of the Costume Culture
• /
• v.7 no.1
• /
• pp.141-153
• /
• 1999

To be successful, Korean exporters must understand how importers identify and select suppliers. This empirically based study investigate Korean exporter\`s perceptions of the supply selection criteria and information sources in US importers use. The specific purposes of this study were to identify the importance of the supply selection criteria and information sources and to examine the effects of the amount of export on the supply selection criteria and information sources in US importer use. For this study, data were obtained from Korean exporters by means of self-administered questionnaires. The questionnaires consisted of a series of statements covering a broad of specific selection criteria and information sources and exports\` characteristics including average annual amount of export. Using a base of 312 exporters, data were analysed by using mean, one-way ANOVA, and Ducan test. Major findings if this study summarized as follows; 1) Korean exporters perceived that US importers would place importances on product price, deliverly reliability, product wordsmanship-quality, and length of deliverly lead-time, in orders. Also, the more amount of export was, the higher product wordsmanship-quality, availability of piece goods and trims, and communication channel were importantly rate. 2) Korean exporters considered the third party sources, such as recommendation from trade association and buying office and import agency, as the most important information source in US importer use. Also, There was tendency that the more amount of export was, the more information sources on suppliers was importantly evaluated. From this study, several recommendation were suggested forward to encourage export in international apparel market.