• ETRI Journal
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• 제40권1호
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• pp.26-38
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• 2018

To overcome considerable path loss in millimeter-wave propagation, high-gain directional beamforming is considered to be a key enabling technology for outdoor 5G mobile networks. Associated with beamforming, this paper investigates propagation power loss characteristics in two aspects. The first is beamwidth effects. Owing to the multipath receiving nature of mobile environments, it is expected that a narrower beamwidth antenna will capture fewer multipath signals, while increasing directivity gain. If we normalize the directivity gain, this narrow-beamwidth reception incurs an additional power loss compared to omnidirectional-antenna power reception. With measurement data collected in an urban area at 28 GHz and 38 GHz, we illustrate the amount of these additional propagation losses as a function of the half-power beamwidth. Secondly, we investigate power losses due to steering beam misalignment, as well as the measurement data. The results show that a small angle misalignment can cause a large power loss. Considering that most standard documents provide omnidirectional antenna path loss characteristics, these results are expected to contribute to mmWave mobile system designs.

• 벤처창업연구
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• 제8권2호
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• pp.53-61
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• 2013

본 연구는 프로스펙트이론을 적용하여 납세순응 문제를 다루었다. 납세순응의 결과는 소득 신고에서 나타나므로 원천징수에 따라 추가 납부와 환급 상황에 있는 두 개의 기업과 하나의 창업기업을 대상으로 세무대리인의 소득 신고액을 실험 기법으로 조사하였다. 프로스펙트이론에서는 이득 영역에서는 위험 회피, 손실 영역에서는 위험 선호로 의사결정자의 가치함수가 달라지므로 추가 납부 상황의 기업은 손실 상황의 기업으로 보아 소득 신고액이 감소하고, 환급 상황의 기업은 이득 상황의 기업으로 보아 소득 신고액이 증가한다고 본다. 창업기업은 준거점이 zero이므로 손실 상황이 아니라고 볼 수 있으나 기업의 재무 상태는 초기 투자로 인해 손실 상황일 것이다. 따라서 창업기업은 손실 상황의 기업과 동일한 방향으로 소득 신고가 이루어질 것이라고 볼 수 있다. 이에 대한 가설을 검증한 결과 창업기업이 소득 신고액이 가장 낮고 그 다음이 손실 상황의 기업이고 이익 상황의 기업이 소득 신고액이 가장 많았다. 두 번째 납세순응행위에 영향을 미치는 또 하나의 중요한 요인은 세무조사 적발률이다. 세무조사 적발률을 높이면 납세순응이 커진다. 이에 대한 가설을 검증한 결과 손실 상황의 기업, 이익 상황의 기업은 세무조사 적발률이 높아지면 소득 신고액이 증가하였다. 그러나 창업기업에 대해서는 통계적으로 검증이 되지 못하였다. 세 번째 세무대리인의 납세자 옹호성향과 위험선호 성향이 강할수록 프레이밍 효과가 커질 것이라는 가설에 대한 검증 결과 세무 대리인의 납세자 옹호성향이 증가할수록 창업기업과 손실 상황의 기업의 소득 신고액은 감소하고 이익 상황의 기업의 소득 신고액은 증가하였고 통계적으로 지지를 받았다. 반면 세무대리인의 위험선호 성향이 증가할수록 창업기업과 손실 상황의 기업의 소득 신고액은 감소하고 통계적으로 지지를 받았으나 이익 상황의 기업에 대해서는 통계적 지지를 받지 못하였다. 본 연구는 원천징수율, 적발률과 가산세율 등이 납세 순응 행위나 태도에 미치는 영향을 조사함으로써 정부의 정책 결정, 기업의 세무대리인 선정, 세무대리인의 적정 소득 신고 등에 도움이 될 것이며, 창업기업에 대해서는 최초의 연구이므로 그 의미가 더 있다.

• 여성건강간호학회지
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• 제20권2호
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• pp.155-162
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• 2014

Purpose: The purpose of this study was to identify factors influencing desired postnatal weight loss in women after birth. Methods: With correlational survey design, 191women of the study participants completed questionnaires on their desired postnatal weight loss and related factors, and body and health concerns during their hospitalization after birth. Data were collected from February to May, 2011. Data were analyzed using t-test, ANOVA, Pearson correlation coefficients, and multiple linear regression. Results: The women's gestational weight gain, pre-pregnant BMI, body concerns, expected time to reach the desired weight after birth and health concerns were identified as factors influencing desired postnatal weight loss in women after birth. The model explained 68% of the variance. Conclusion: Results suggest that nurses in women's health care should consider women's gestational weight, pre-pregnant BMI and their body concerns, health concerns and expected time to reach the desired weight after birth when developing weight management program for women after birth.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1493-1495
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• 1997

Cropping of head and tail ends of rod in wire Rolling Process is required to aviod roll damage, and prevent cobbles. In order to reduce the crop loss, the new crop control system for rotary shear of Wire rolling Process has been developed. Performance shows the developed system cut precisely within setting length. As a result, it is expected to increase the yield ratio of products about 0.2 percent and stabilize the operantional condition.

• Journal of the Korean Data and Information Science Society
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• 제20권6호
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• pp.1191-1197
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• 2009

Most Bayesian approaches to model selection of wavelet analysis have drawbacks that computational cost is expensive to obtain accuracy for the fitted unknown function. To overcome the drawback, this article introduces loss functions which are criteria for level dependent threshold selection in wavelet based Bayesian methods with arbitrary size and regular design points. We demonstrate the utility of these criteria by four test functions and real data.

• Journal of the Korean Statistical Society
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• 제32권3호
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• pp.289-298
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• 2003

We consider the estimation problem for the scale parameter of the Rayleigh distribution using weighted balanced loss function (WBLF) which reflects both goodness of fit and precision. Under WBLF, we obtain the optimal estimator which creates a kind of balance between Bayesian and non-Bayesian estimation. We also deal with the estimation of R ＝ P(Y < X) when Y and X are two independent but not identically distributed Rayleigh distribution under squared error loss function.

• 산업경영시스템학회지
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• 제39권3호
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• pp.10-17
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• 2016

Control Chart is a graph which dots the characteristic values of a process. It is the tool of statistical technique to keep a process in controlled condition. It is also used for investigating the state of a process. Therefore many companies have used Control Chart as the tool of statistical process control (SPC). Products from a production process represent accidental dispersion values around a certain reference value. Fluctuations cause of quality dispersion is classified as a chance cause and a assignable cause. Chance cause refers unmanageable practical cause such as operator proficiency differences, differences in work environment, etc. Assignable cause refers manageable cause which is possible to take actions to remove such as operator inattention, error of production equipment, etc. Traditionally ${\bar{x}}-R$ control chart or ${\bar{x}}-s$ control chart is used to find and remove the error cause. Traditional control chart is to determine whether the measured data are in control or not, and lets us to take action. On the other hand, RNELCC (Reflected Normal Expected Loss Control Chart) is a control chart which, even in controlled state, indicates the information of economic loss if a product is in inconsistent state with process target value. However, contaminated process can cause control line sensitive and cause problems with the detection capabilities of chart. Many studies on robust estimation using trimmed parameters have been conducted. We suggest robust RNELCC which used the idea of trimmed parameters with RNEL control chart. And we demonstrate effectiveness of new control chart by comparing with ARL value among traditional control chart, RNELCC and robust RNELCC.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.324-325
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• 2011

This paper addresses the assessment of voltage sag costs based on the stochastic prediction of voltage sags. When voltage sags below a certain voltage threshold occur at sensitive industrial process, the industrial customer will experience financial damage. In order to mitigate voltage sag costs and devise efficient solutions to mitigate damage, a study on the financial loss assessment of voltage sags is basically needed. In order to assess the voltage sag costs, the expected sag frequency at a sensitive load point should be calculated by using the concept of the area of vulnerability and historical fault statistics. Then, financial loss due to voltage sags can be obtained by multiplying the expected sag frequency by the cost per sag event.

• 대한인간공학회지
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• 제15권2호
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• pp.113-124
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• 1996

This study was initiated to suggest the optimal size intervals for mail-order clothing. The questionnaire survey was carried at 360 women and 50 men who purchased apparels by mail-order. The garment sizes providing at the various mail-order companies in Korea were compared. The garment sizes that consumers wanted to purchase were also investigated. The collected data were analyzed and optimal size intervals for mail-order clothing were decided by the loss function. The results are as follow. 1) The optimal size intervals were varied from 4cm to 7cm. The total expected loss of the apparel sizes suggested in this study was less than that of the current mail-order apparel sizes. When the number of sizes for mail-order clothing is increased, the expected loss was reduced considerably. 2) The mail-order clothing is made for consumers with average body size. 30 The number of garment sizes available by mail-order was under three. 4) Subjects tend to select larger size garments, when the right size garments are not available.

• Communications for Statistical Applications and Methods
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• 제27권3호
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• pp.327-347
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• 2020

We consider a credit portfolio with highly skewed exposures. In the portfolio, small number of obligors have very high exposures compared to the others. For the Bernoulli mixture model with highly skewed exposures, we propose a new importance sampling scheme to estimate the tail loss probability over a threshold and the corresponding expected shortfall. We stratify the sample space of the default events into two subsets. One consists of the events that the obligors with heavy exposures default simultaneously. We expect that typical tail loss events belong to the set. In our proposed scheme, the tail loss probability and the expected shortfall corresponding to this type of events are estimated by a conditional Monte Carlo, which results in variance reduction. We analyze the properties of the proposed scheme mathematically. In numerical study, the performance of the proposed scheme is compared with an existing importance sampling method.