• Communications for Statistical Applications and Methods
• /
• v.26 no.5
• /
• pp.507-517
• /
• 2019

Statistical matching is a method of combining multiple sources of data that are extracted or surveyed from the same population. It can be used in situation when variables of interest are not jointly observed. It is a low-cost way to expect high-effects in terms of being able to create synthetic data using existing sources. In this paper, we propose the several statistical micro matching methods using a multinomial logistic regression model when all variables of interest are categorical or categorized ones, which is common in sample survey. Under conditional independence assumption (CIA), a mixed statistical matching method, which is useful when auxiliary information is not available, is proposed. We also propose a statistical matching method with auxiliary information that reduces the bias of the conventional matching methods suggested under CIA. Through a simulation study, proposed micro matching methods and conventional ones are compared. Simulation study shows that suggested matching methods outperform the existing ones especially when CIA does not hold.

• Annual Conference on Human and Language Technology
• /
• 2019.10a
• /
• pp.60-63
• /
• 2019

사용자와 자연어 음성을 통해 상호작용하는 대화 시스템이 주목받고 있다. 음성 뿐 아니라, 화면을 통해 사용자와 상호작용하는 기능을 제공하는 대화 시스템들이 소개되고 있으며, 최근에는 혼합 현실 환경에서 대화 에이전트가 실제 공간에 존재하는 서비스가 소개되기도 하였다. 본 연구에서는 혼합 현실 환경의 대화 시스템이 현실 세계에 영향을 미칠 수 있는 시스템을 설계하였다. 제안하는 시스템은 서버가 클라이언트와 통신하여 필요 시 적절한 장치를 제어하도록 설계되었다. 본 연구 시스템의 실현가능성을 입증하기 위해 라즈베리파이를 제어할 장치로 사용하였으며, 화면에 보이는 대화 에이전트에게 음성으로 명령하여 전등, 에어컨 등을 제어하는 것이 가능함을 확인하였다.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.3
• /
• pp.221-229
• /
• 2013

In this paper, the image formation by the motion compensation technique for Synthetic Aperture Radar system(SAR) were realized through the computer simulation. The motion compensation technique performed image data with the range compression, the compensation procedure, the azimuth compensation and the noise elimination procedure. The range compression procedure transform the SAR raw data into the frequency domain and correlate with the range reference function and then inversely transform into the time domain. The compensation procedure contain the aircraft fluctuations compensation and the radar image degrading effect elimination procedure which was caused by image formation algorithm itself. The aircraft fluctuations compensation procedure perform the first stage which correct the phase angle and the second stage which calculate the Doppler frequency and determine the coordinate of the received signal. The radar image degrading effect elimination procedure also perform range migration compensation and the image defocussing effect compensation. The azimuth compression procedure transform the compensation data to the frequency domain and correlate with the azimuth reference function. The azimuth correlated data are inversely transformed to the time domain which is called SAR image data. When the above procedure were completed, the image data contains the received signals mixed with noise. The threshold technique was applied to elimination the noise from the mixed image data.

• Journal of Distribution Science
• /
• v.17 no.3
• /
• pp.85-95
• /
• 2019

Purpose - The existing marketing studies using Social Network Analysis have assumed that network structure variables are time-invariant. However, a node's network position can fluctuate considerably over time and the node's network structure can be changed dynamically. Hence, if such a dynamic structural network characteristics are not specified for virtual goods purchase model, estimated parameters can be biased. In this paper, by comparing a time-invariant network structure specification model(base model) and time-varying network specification model(proposed model), the authors intend to prove whether the proposed model is superior to the base model. In addition, the authors also intend to investigate whether coefficients of network structure variables are random over time. Research design, data, and methodology - The data of this study are obtained from a Korean social network provider. The authors construct a monthly panel data by calculating the raw data. To fit the panel data, the authors derive random effects panel tobit model and multi-level mixed effects model. Results - First, the proposed model is better than that of the base model in terms of performance. Second, except for constraint, multi-level mixed effects models with random coefficient of every network structure variable(in-degree, out-degree, in-closeness centrality, out-closeness centrality, clustering coefficient) perform better than not random coefficient specification model. Conclusion - The size and importance of virtual goods market has been dramatically increasing. Notwithstanding such a strategic importance of virtual goods, there is little research on social influential factors which impact the intention of virtual good purchase. Even studies which investigated social influence factors have assumed that social network structure variables are time-invariant. However, the authors show that network structure variables are time-variant and coefficients of network structure variables are random over time. Thus, virtual goods purchase model with dynamic network structure variables performs better than that with static network structure model. Hence, if marketing practitioners intend to use social influences to sell virtual goods in social media, they had better consider time-varying social influences of network members. In addition, this study can be also differentiated from other related researches using survey data in that this study deals with actual field data.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.3 no.2
• /
• pp.95-108
• /
• 1978

This paper discusses an application of mathematical programming techniques in the paper industry in determining optimal parent roll widths. Parent rolls are made from the reels produced at wide paper machines by slitting them to more manageable widths. The problem is finding a set of the slitting patterns that will minimize the trim loss involved in the sheeting operation. Two programming models, one linear and one mixed integer linear, are presented in this paper. Also presented are the computational experience, the model sensitivity, and the comparison of the optimal solutions with the simulated operational data.

• Korean Management Science Review
• /
• v.12 no.1
• /
• pp.139-156
• /
• 1995

This study addresses basic requirements for mathematical programming software, discusses considerations in designing these software, implementation issues facing in these types of applications development, and shows some examples of codes being developed in the course. This type of projects requires long and ever-changing evolutionary phases. The experience is therefore, valuaable in suggesting some useful hints which may be salvaged for similar projects as well as providing reusable codes. In particular, scanning and parsing the free-format inputs, symbol table management, mixed-language programming, and data structures dealing with large sparse matrices are indispensable to many management science software development. Extensions to be made are also discussed.

• Communications for Statistical Applications and Methods
• /
• v.10 no.3
• /
• pp.845-857
• /
• 2003

We explore the use of genetic programming to evolve decision trees directly for classification problems with both discrete and continuous predictors. We demonstrate that the derived hypotheses of standard algorithms can substantially deviated from the optimum. This deviation is partly due to their top-down style procedures. The performance of the system is measured on a set of real and simulated data sets and compared with the performance of well-known algorithms like CHAID, CART, C5.0, and QUEST. Proposed algorithm seems to be effective in handling problems caused by top-down style procedures of existing algorithms.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.11a
• /
• pp.419-422
• /
• 2005

This paper is examined the properties of Haeju sea sand for concrete. As result, the water absorbtion ratio and the contents of shell and microfines of Haeju sea sand was high. We would expected to utilize the results of this study as a basic data for quality control of Ready Mixed Concrete.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1998.04a
• /
• pp.261-266
• /
• 1998

The purpose of this study is to present the reference data on the development of undispersed underwater mortar for augered pile under various replacement ratio of fly-ash. According to the experimental results, when 10% of fly-ash is mixed under mix proportion of 1:1.5(c:s), as strength and shrinkage decrease slightly, whereas fluidity increase, high quality mortar for augered pile can be achieve in case above condition is applied.

• Structural Engineering and Mechanics
• /
• v.61 no.3
• /
• pp.381-387
• /
• 2017

In this paper we investigate the theory of micropolar thermoelastic bodies whose micro-particles possess microtemperatures. We transform the mixed initial boundary value problem into a temporally evolutionary equation on a Hilbert space and after that we prove the existence and uniqueness of the solution. We also approach the study of the continuous dependence of solution upon initial data and loads.