• 정보화정책
• /
• 제27권1호
• /
• pp.72-91
• /
• 2020

공개된 프로필을 기반으로 개인정보에 대한 접근이 상대적으로 자유로운 개방형 SNS와 미리 소통할 지인의 범위를 제한하여 개인정보의 유출에 덜 취약한 폐쇄형 SNS에서 프라이버시 역설 현상이 다르게 관측될 수 있다는 개연성에 기인하여, 본 연구에서는 SNS를 개방형과 폐쇄형으로 구분하고, 어떠한 SNS 활동에서 프라이버시 역설이 성립하는지를 살펴보았다. 실증분석의 결과는 다음과 같다. 첫째, SNS 사용 여부의 경우, 전체적인 SNS 활동에서는 프라이버시 역설이 성립하지만, 개방형 및 폐쇄형 SNS에 따라 다른 결론이 도출되었다. 특히, 침해에 더 취약한 개방형 SNS에서는 프라이버시 염려가 증가함에 따라 개인들이 합리적이고 바람직하게 SNS 활동을 감소키는 식으로 대응하는 것이 관찰되었다. 둘째, SNS 사용 강도의 경우, (i) 헤비 유저가 라이트 유저에 비해 프라이버시 침해의 개연성을 더 심각하게 인식하여 프라이버시 염려의 증가에 따라 사용 강도를 감소하는 식의 합리적인 반응을 하며, 또한 (ii) 이러한 경향이 개인정보 침해에 취약한 개방형 SNS에서 더욱 뚜렷하게 관찰되는 것으로 나타났다. 이에 따라 SNS 활동을 구분하지 않고 통합적으로 분석하여 프라이버시 역설의 존재를 주장하는 것은 일종의 '구성의 오류(Fallacy of Composition)'를 범하는 것으로 해석할 수 있다.

• Wind and Structures
• /
• 제19권6호
• /
• pp.623-647
• /
• 2014

In this paper, a probability distribution which is consistent with the observed phenomenon at the roof corner and, also on other portions of the roof, of a low-rise building is proposed. The model is consistent with the choice of probability density function suggested by the statistical thermodynamics of open systems and turbulence modelling in fluid mechanics. After presenting the justification based on physical phenomenon and based on statistical arguments, the fit of alpha-stable distribution for prediction of extreme negative wind pressure coefficients is explored. The predictions are compared with those actually observed during wind tunnel experiments (using wind tunnel experimental data obtained from the aerodynamic database of Tokyo Polytechnic University), and those predicted by using Gumbel minimum and Hermite polynomial model. The predictions are also compared with those estimated using a recently proposed non-parametric model in regions where stability criterion (in skewness-kurtosis space) is satisfied. From the comparisons, it is noted that the proposed model can be used to estimate the extreme peak negative wind pressure coefficients. The model has an advantage that it is consistent with the physical processes proposed in the literature for explaining large fluctuations at the roof corners.

• 한국전자거래학회지
• /
• 제5권1호
• /
• pp.55-73
• /
• 2000

Recently; EC(Electronic Commerce) is increasing with high speed based on the expansion of Internet. EC which is done on the cyber space through Internet has strong point like independence from time and space. On the contrary, it also has weak point like security problem because anybody can access easily to the system due to open network attribute of Internet. Therefore, we need the solutions that protect the security problem for safe and useful EC activity. One of these solutions is the implementation of strong cipher algorithm. NC(Nonpolynomial Complete) cipher algorithm proposed in this paper is good for the security and it overcome the limit of current 64bits cipher algorithm using 128bits key length for input, output and encryption key, Moreover, it is designed for the increase of calculation complexity and probability calculation by adapting more complex design for subkey generation regarded as one of important element effected to encryption. The result of simulation by the comparison with other cipher algorithm for capacity evaluation of proposed NC cipher algorithm is that the speed of encryption and decryption is 7.63 Mbps per block and the speed of subkey generation is 2,42 μ sec per block. So, prosed NC cipher algorithm is regarded as proper level for encryption. Furthermore, speed of subkey generation shows that NC cipher algorithm has the probability used to MAC(Message Authentication Code) and block implementation of Hash function.

• The Journal of Asian Finance, Economics and Business
• /
• 제7권11호
• /
• pp.241-250
• /
• 2020

This study examines the relationship between the attributes of board structure and the likelihood of financial distress for the non-financial sector of an emerging market characterized by concentrated ownership and family-controlled business. The present study utilized panel logistic regression to estimate the relationship between board structure attributes and the likelihood of financial distress. We used Altman Z-Score as a proxy for firm financial distress, as this tool measures the financial distress inversely. The study finds a significant relationship between board size and the likelihood of financial distress. The results show that a one-unit increase in board size would decrease the probability of financial distress by 3.4%. Further, we observe that a greater level of board independence is associated with a lower likelihood of financial distress. A one-unit increase in board independence would decrease the probability of financial distress by 20.4%. We also find a significant positive impact of leverage on the likelihood of financial distress. The present study contributes to the body of literature on board structure attributes and likelihood of financial distress in emerging markets, like Pakistan. Furthermore, the findings would be beneficial for corporate policymakers and investors in formulating corporate financial strategy and predicting business failure.

• 한국멀티미디어학회논문지
• /
• 제12권8호
• /
• pp.1182-1189
• /
• 2009

컴퓨터 기반 교육의 잠재적인 이점은 개별화 교습이다. 결국 수준별 교육과정의 운영과 열린 교육의 실천을 위하여 어떻게 학습자 개개인에 대해서 신속하고 정확하게 평가할 수 있는가에 대한 문제가 제기된다. 본 연구에서는 평가를 위한 문항 수가 두드러지게 감소하면서 반면에 합격과 불합격 판정이 비교적 정확한 기존의 SPRT(Sequential Probability Ratio Testing) 판정 방법에 대한 문제점을 보완하여 보다 최적의 판정을 내릴 수 있는 방안을 시뮬레이션 연구를 통하여 제안한다. 이를 위하여 실제 측정에 의해서 얻어진 피험자 자료를 활용하여 SPRT판정의 정확도 검증을 위한 시뮬레이션과 최적의 SPRT판정을 위한 초기 설정치와 다단계 (Multilevel) SPRT 모형 및 판정 기준을 제시하고 시뮬레이션을 통하여 타당성을 알아본다.

• 한국음향학회:학술대회논문집
• /
• 한국음향학회 1994년도 FIFTH WESTERN PACIFIC REGIONAL ACOUSTICS CONFERENCE SEOUL KOREA
• /
• pp.806-811
• /
• 1994

Two kinds of static and dynamic state estimation methods are newly discussed for the problem of the measurement disturbance of environmental low-frequency noise in the presence of wind-induced noise. First, the probability characteristics of wind-induced noise are discussed in the form of probability distribution conditioned by wind speed, based on the simultaneous observation of the wind-induced noise and wind speed near a microphone. Next, especially form the viewpoint of simplicity for practical use, two kinds of static and dynamic state estimation methods are discussed. The static estimation method using the information on wind speed is fundamentally supported by the conservation principle of energy sum. The dynamic one is the method by using a recursive digital filter with the parameters successively renewed by the information on wind speed. This can be also simplified by using well-know Kalman filter under the assumption of the Gaussian distribution. The effectiveness of proposed two estimation methods are shown through experiments under a breezy condition in the open filed.

• 한국해양공학회지
• /
• 제37권1호
• /
• pp.20-30
• /
• 2023

Modeling a nonlinear ocean wave is one of the primary concerns in ocean engineering and naval architecture to perform an accurate numerical study of wave-structure interactions. The high-order spectral (HOS) method, which can simulate nonlinear waves accurately and efficiently, was investigated to see its capability for nonlinear wave generation. An open-source (distributed under the terms of GPLv3) project named "HOS-ocean" was used in the present study. A parametric study on the "HOS-ocean" was performed with three-hour simulations of long-crested ocean waves. The considered sea conditions ranged from sea state 3 to sea state 7. One hundred simulations with fixed computational parameters but different random seeds were conducted to obtain representative results. The influences of HOS computational parameters were investigated using spectral analysis and the distribution of wave crests. The probability distributions of the wave crest were compared with the Rayleigh (first-order), Forristall (second-order), and Huang (empirical formula) distributions. The results verified that the HOS method could simulate the nonlinearity of ocean waves. A set of HOS computational parameters was suggested for the long-crested irregular wave simulation in sea states 3 to 7.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제11권6호
• /
• pp.3188-3207
• /
• 2017

In this paper, we propose an image enhancement algorithm to improve license plate extraction rate in various environments (Day Street, Night Street, Underground parking lot, etc.). The proposed algorithm is composed of image enhancement algorithm and license plate extraction algorithm. The image enhancement method can improve an image quality of the degraded image, which utilizes a histogram information and overall gray level distribution of an image. The proposed algorithm employs an interpolated probability distribution value (PDV) in order to control a sudden change in image brightness. Probability distribution value can be calculated using cumulative distribution function (CDF) and probability density function (PDF) of the captured image, whose values are achieved by brightness distribution of the captured image. Also, by adjusting the image enhancement factor of each part region based on image pixel information, it provides a function that can adjust the gradation of the image in more details. This processed gray image is converted into a binary image, which fuses narrow breaks and long thin gulfs, eliminates small holes, and fills gaps in the contour by using morphology operations. Then license plate region is detected based on aspect ratio and license plate size of the bound box drawn on connected license plate areas. The images have been captured by using a video camera or a personal image recorder installed in front of the cars. The captured images have included several license plates on multilane roads. Simulation has been executed using OpenCV and MATLAB. The results show that the extraction success rate is more improved than the conventional algorithms.

• Journal of Computing Science and Engineering
• /
• 제11권4호
• /
• pp.142-151
• /
• 2017

Spontaneous intracerebral hemorrhage (sICH) has a high mortality rate. Research has demonstrated that sICH occurrence is related to weather conditions; therefore, this study used the decision tree method to explore the impact of climatic risk factors on sICH at different ages. The Taiwan National Health Insurance Research Database (NHIRD) and other open-access data were used in this study. The inclusion criterion was a first-attack sICH. The decision tree algorithm and random forest were implemented in R programming language. We defined a high risk of sICH as more than the average number of cases daily, and the younger, middle-aged and older groups were calculated as having 0.77, 2.26 and 2.60 cases per day, respectively. In total, 22,684 sICH cases were included in this study; 3,102 patients were younger (<44 years, younger group), 9,089 were middle-aged (45-64 years, middle group), and 10,457 were older (>65 years, older group). The risk of sICH in the younger group was not correlated with temperature, wind speed or humidity. The middle group had two decision nodes: a higher risk if the maximum temperature was >$19^{\circ}C$ (probability = 63.7%), and if the maximum temperature was <$19^{\circ}C$ in addition to a wind speed <2.788 (m/s) (probability = 60.9%). The older group had a higher risk if the average temperature was >$23.933^{\circ}C$ (probability = 60.7%). This study demonstrated that the sICH incidence in the younger patients was not significantly correlated with weather factors; that in the middle-aged sICH patients was highly-correlated with the apparent temperature; and that in the older sICH patients was highly-correlated with the mean ambient temperature. "Warm" cold ambient temperatures resulted in a higher risk of sICH, especially in the older patients.

• Wind and Structures
• /
• 제3권3호
• /
• pp.177-191
• /
• 2000

This paper presents an approach for evaluating directionality effects for both wind speeds and wind loads in hurricane-prone regions. The focus of this study is on directional wind loads on low-rise structures. Using event-based simulation, hurricane directionality effects are determined for an open-terrain condition at various locations in the southeastern United States. The wind speed (or wind load) directionality factor, defined as the ratio of the N-year mean recurrence interval (MRI) wind speed (or wind load) in each direction to the non-directional N-year MRI wind speed (or wind load), is less than one but increases toward unity with increasing MRI. Thus, the degree of conservatism that results from neglecting directionality effects decreases with increasing MRI. It may be desirable to account for local exposure effects (siting effects such as shielding, orientation, etc.) in design. To account for these effects in a directionality adjustment, the factor described above for open terrain would need to be transformed to other terrains/exposures. A "local" directionality factor, therefore, must effectively combine these two adjustments (event directionality and siting or local exposure directionality). By also considering the direction-specific aerodynamic coefficient, a direction-dependent wind load can be evaluated. While the data necessary to make predictions of directional wind loads may not routinely be available in the case of low-rise structures, the concept is discussed and illustrated in this paper.