• 한국공간정보시스템학회 논문지
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• 제11권3호
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• pp.55-62
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• 2009

유비쿼터스 컴퓨팅 환경에서의 LBS, 즉 u-LBS는 실세계의 수많은 객체가 위치정보와 밀접히 연관된 대용량 데이타를 대상으로 한다. 특히, 사용자의 위치 정보와 관련하여 검색하려고 하는 객체인 POI에 대한 빠른 검색이 중요하다. 따라서 u-LBS에서 POI의 효율적인 검색을 위한 인덱스 구조에 대한 연구가 필요하다. 본 논문에서는 u-LBS에서 정적 POI를 대상으로 이를 효율적으로 검색하기 위한 DGR-Tree를 제시한다. DGR-Tree는 변형된 R-Tree를 기본 인덱스로 하고 동적 레벨 그리드를 보조 인덱스로 사용하는 구조이다. DGR-Tree는 점 데이타에 적합하도록 최적화하고 있으며 리프 노드 간 겹침 문제를 해결한다. DGR-Tree에서 동적 레벨 그리드는 점 데이타의 밀집도에 따라 동적으로 구성되며, 각 셀은 DGR-Tree의 리프 노드와 연계를 위한 포인터를 저장하여 리프 노드를 직접 접근하도록 함으로써 인덱스 접근 성능을 향상시킨다. 또한, 본 논문에서는 DGR-Tree를 위한 KNN 검색 알고리즘을 제시한다. 이 알고리즘에서는 KNN 검색 시 후보 셀에 빠르게 접근하기 위하여 동적 레벨 그 리드를 활용하며, 후보를 노드별로 구분하여 저장함으로써 후보 리스트 내에서의 정렬 비용을 감소시킨다. 마지막으로 실험을 통해 DGR-Tree의 우수성을 입증하였다.

• 한국측량학회지
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• 제39권1호
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• pp.29-40
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• 2021

범죄, 화재, 교통사고 등 국민의 안전을 위협하는 위험인자들은 지역적 맥락과 공간적 특성을 가지고 있다. 지역마다 서로 다른 위험환경을 가지고 있으므로 교통사고, 화재, 범죄, 생활안전 분야별로 위험요소의 공간적 패턴을 분석할 필요가 있다. 본 연구는 전국 기초자치단체를 대상으로 분야(교통사고, 화재, 범죄, 생활안전, 자살, 감염병)별 안전등급을 측정한 지표인 지역안전지수의 공간적 분포 패턴을 분석하는데 연구의 목적이 있다. 지역안전지수의 공간적 자기상관성 분석을 위해 전역적 공간자기상관분석(Global Moran's I)과 Local Moran's I를 활용한 LISA(Local Indicators of Spatial Association) 분석, Getis-Ord's G⁎i 분석을 실시하였다. 분석결과 교통사고, 화재, 자살의 안전지수 분포는 범죄, 생활안전, 감염병의 안전지수보다 공간적으로 집중(clustered) 경향을 보였다. 지역간 유의미한 공간적 연관성을 분석한 LISA 분석결과에 따르면, 수도권 지역이 다른 도시에 비하여 지역안전통합지수를 기준으로 비교적 안전한 지역인 것으로 나타났다. 또한 Getis-Ord's G⁎i 통계값을 활용한 핫스팟분석 결과 안전 취약지역의 군집인 3개의 핫스팟(강원도 삼척시, 경상북도 청송군, 전라북도 김제시)과 전반적인 안전 수준이 높은 군집인 15개의 콜드스팟이 도출되었다. 이러한 연구 결과는 안전 수준 취약지역의 공간적 분포와 패턴을 파악하여 안전 지수 개선을 위한 정책 수립시 기초자료로 활용될 수 있다.

• Structural Engineering and Mechanics
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• 제62권3호
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• pp.365-372
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• 2017

Reliability analysis is a probabilistic approach to determine a safety level of a system. Reliability is defined as a probability of a system (or a structure, in structural engineering) to functionally perform under given conditions. In the 1960s, Basler defined the reliability index as a measure to elucidate the safety level of the system, which until today is a commonly used parameter. However, the reliability index has been formulated based on the pivotal assumption which assumed that the considered limit state function is normally distributed. Nevertheless, it is not guaranteed that the limit state function of systems follow as normal distributions; therefore, there is a need to define a new reliability index for no-normal distributions. The main contribution of this paper is to define a sophisticated reliability index for limit state functions which their distributions are non-normal. To do so, the new definition of reliability index is introduced for non-normal limit state functions according to the probability functions which are calculated based on the convolution theory. Eventually, as the state of the art, this paper introduces a simplified method to calculate the reliability index for non-normal distributions. The simplified method is developed to generate non-normal limit state in terms of normal distributions using series of Gaussian functions.

• 품질경영학회지
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• 제36권4호
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• pp.102-116
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• 2008

The most widely used models to study the quality of service are the SERVQUAL and SERVPERF models that measure service mechanisms. This paper is to estimate service efficiency and consistency for Retail Industry. We tried to measure the service quality and overall satisfaction by using DEA and PCI, degree of combination and top2box which is a little bit different methodology from traditional ones. Rather than using the usual method of converting the service quality index by mean value, the Service Efficiency Index(SEI) and Service Quality Consistency Index(SQCI) are used to measure the efficiency and consistency level, which in turn can be used as the new service quality indices. The result of SEI and SQCI show the efficiency frontier in retail industry that 6 DMUs are analyzed relative efficient DMUs, 12DMUs are inefficient DMUs and retail Industry consistency level appeared low(0.35-0.47) Also, there is a significant difference in terms of efficiency and consistency in the each retail industry. Finally, we showed the summarized result as the Effi-Con Matrix.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계 학술대회논문집(수송기계편)
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• pp.186-189
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• 2005

Since human listening is very sensitive to sound, a subjective index of a sound quality is required. Therefore, in the analysis for each situation, the sound evaluation is composed with sound quality factor. Many researchers spends their effort to make a more reliable and more accurate of sound in term of sound quality index for various system noise. In this study a reliable index is constructed and analyzed using correlation analysis, regression analysis and weighting factor for each sound quality factor. We have made the sound quality index that agrees with more than human subjective sensitivity which apply to various sound quality metrics. Also we applied a 'grade' metric to jury for sound evaluation, analyzed relation between sound duality index and sound quality grade. Then we will judge the sound quality level according to the sound quality grade scheme.

• Geomechanics and Engineering
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• 제4권3호
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• pp.219-227
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• 2012

Pavement management systems require systematic monitoring of pavement surfaces to determine preventive and corrective maintenance. The process involves the accumulation of large amounts of visual data, typically obtained from site visitation. The pavement surface condition is then correlated to a pavement distress index that is based on a scoring system previously established by state or federal agencies. The scoring system determines if the pavement section requires maintenance, overlay or reconstruction. One of the surface distresses forming part of the overall pavement distress index is the Alligator Crack Index (AC Index). The AC Index involves the visual evaluation of the crack severity of a section of a pavement as being low, medium, or high. This evaluation is then integrated into a formula in order to obtain the AC Index. In this study a quantification of the visual evaluation of the severity of alligator cracking is carried out using photographs and the fractal dimension concept from fractal theory. Pavements with low levels of cracking were found to have a fractal dimension equal to 1.051. Pavements with moderate levels of cracking had a fractal dimension equal to 1.1754. Pavements with high degrees of cracking had a fractal dimension that varied between 1.5037 (high) and 1.7111 (very high). Pavements with a level of cracking equal to 1.8976 represented pavements that disintegrated and developed potholes. Thus, the visual evaluation of the state of cracking of a pavement (the AC Index) could be enhanced with the use of the fractal dimension concept from fractal theory.

• International Journal of Automotive Technology
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• 제7권1호
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• pp.43-49
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• 2006

In this paper, an index for the evaluation of a vehicle intake booming noise and intake sound quality were developed through a correlation analysis and a multiple factor regression analysis of objective measurement and subjective evaluation data. At first, an intake orifice noise was measured at the wide-open throttle test condition. And then, an acoustic transfer function between intake orifice noise and interior noise at the steady state condition was estimated. Simultaneously, subjective evaluation was carried out with a 10-scale score by 8 intake noise and vibration expert evaluators. Next, the correlation analysis between the psychoacoustic parameters derived from the measured data and the subjective evaluation was performed. The most critical factor was determined and the corresponding index for intake booming noise and sound quality are obtained from the multiple factor regression method. And, the optimal design of intake system was studied using the booming noise and the sound quality evaluation index for expectation performance of intake system. Conclusively, the optimal designing parameters of intake system from noise level and sound quality whose point of view were extracted by adapting comparative weighting between the booming noise and sound quality evaluation index, which optimized the process. These work could be represented guideline to system engineers, designers and test engineers about optimization procedure of system performance by considering both of noise level and sound quality.

• Human Ecology Research
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• 제59권1호
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• pp.127-141
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• 2021

This study evaluates the financial status of Korean households using Household Financial Composite Index (HFCI) proposed in the preceding study. We analyzed 1,566 households with four persons aged 30-59 using raw data from the Korea Labor Panel Survey in 2016. The analysis results are as follows. First, HFCI was found to be 57.0 out of 100. Growth Index as one of three subindices was 11.1, which was significantly lower with 65.0 points for Status Index and 61.1 points for the Stability Index. Second, for households with male household owners, the overall financial score was 57.0, while that with female owners was almost similar with 57.2. HFCI was similar for the owner's age groups, but for Status Index, 58.5 for 30s, compared with 66.1 for 40s and 67.1 for 50s. The higher the education level of household owners, the better HFCI, with 53.2 high school graduates and 64.8 graduate graduates, showing a high gap of 11.6 points. HFCI for households living in owned housing was highest at 60.0, while that for rented housing was 40.7. Third, after controlling other effects, it was found that HFCI differed according to the level of education and ownership of housing living. Householder's gender was not found as a significant factor on HFCI. Status Index The 40s and 50s was higher than those in their 30s. Fourth, households were divided into three groups based on HFCI, named as risk, average and secure groups. HFCI for the risk group was 26.8, which was lower than 78.6 for the secure group, with a Status Index of 19.3. Households in their 50s and graduate school graduates were significantly included in the list of secure groups than others.

• 대한교통학회지
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• 제24권2호
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• pp.53-63
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• 2006

본 연구의 목적은 국내 교통산업 서비스 지수를 산정하고 산정된 지수의 활용 가능성을 모색하는 것이다. 교통사업 서비스지수는 도로, 철도, 항공, 해운부문 등 국내의 여객 및 화물운송 서비스 활동수준을 나타내는 월별 지표로서, 개별 여객수송 및 화물운송 실적자료를 이용하여 산정되었다. 구체적으로 1995년 1월${\sim}$2004년 12월까지의 도로, 철도, 항공, 해운부문의 여객수송실적(인-km)과 화물운송실적(톤) 자료들이 이용되었다 국내 개별 교통산업 부문의 여객 및 화물 운송수입 자료들을 활용하여 개별 수송실적지수들의 가중치 자료를 산출하였으며, 개별 교통산업 서비스 지수(여객지수, 화물지수 및 종합지수)는 라스파이레스 지수와 파쉐 지수에서 일반적으로 발생하는 대체편의를 줄일 수 있는 피셔이상지수를 이용하여 산정되었다. 그 결과, 여객지수보다는 화물지수와 종합지수가 경제현황을 보다 잘 설명하는 것으로 분석되었고, 종합지수를 기준으로 할 때 교통산업 서비스 지수는 국내 경기순환주기에 비해 정점에서는 약18개월, 저점에서는 약3개월 후행하는 것으로 분석되었다. 그럼에도 불구하고 교통산업 서비스 지수의 공식적인 산정과 활용을 위해서는 신뢰성 있고 시의성 있는 시계열 자료의 구축이 필수적이며, 다양한 지수 산정 방법론의 개발도 요구된다.

• 한국물환경학회지
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• 제34권5호
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• pp.514-536
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• 2018

GPI (Group Pollution Index) using 29 indicator groups of Korean benthic macroinvertebrates was proposed in 1992, a higher category taxa-level index developed for rapid field assessment of organic water pollution. This study was performed to revise the assessment scheme of GPI based on taxonomic performance and ecological information accumulated since 1992. The original GPI was renamed SBMI (Simple Benthic Macroinvertebrates Index), and SBMI was based on saprobic valency of 26 indicator groups composed of higher category taxa (mainly family ~ phylum) excluding some genus or species-level taxa. SBMI revealed highly significant correlation with concentration of 5-day biochemical oxygen demand ($BOD_5$) (correlation coefficient r = 0.78, n = 569 sites), total suspended solids (r = 0.69), and total phosphorus (r = 0.77). Also, SBMI revealed strong correlation with Shannon-Weaver's species diversity (r = -0.85), Margalef's species richness (r = -0.85), and McNaughton's dominance (r = 0.83). Determination coefficient of SBMI to concentration of water quality items and values of community indices such as species diversity was 3 ~ 8 % and approximately 11 ~ 14 % higher than that of GPI, respectively. Correlation between SBMI and water quality factors or community indices such as species diversity did not reveal much difference compared to that of species-level indices, such as BMI (Benthic Macroinvertebrates Index) and ESB (Ecological Score of Benthic Macroinvertebrates). SMBI is a simple-qualitative index with higher category taxa easily identified, and is applicable for rapid field assessment of water environment impairment.