• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권2호
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• pp.1234-1249
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• 2017

One of the difficulties developers encounter in maintaining tasks of a large-scale software system is the updating of suitable libraries on time. Developers tend to miss or make mistakes when searching for and choosing libraries during the development process, or there may not be a stable library for the developers to use. We present a novel approach for helping developers modify software easily and on time and avoid software failures. Using a tool previously built by us called GPES, we collected information of projects, such as abstract syntax trees, tokens, software metrics, relations, and evolutions, for our experiments. We analyzed the contexts of source codes in existing projects to predict changes automatically and to recommend suitable libraries for the projects. The collected data show that researchers can reduce the overall cost of data analysis by transforming the extracted data into the required input formats with a simple query-based implementation. Also, we manually evaluated how the extracted contexts are similar to the description and we found that a sufficient number of the words in the contexts is similar and it might help developers grasp the domain of the source codes easily.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권2호
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• pp.709-730
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• 2017

To address the challenge of unprecedented growth in mobile data traffic, ultra-dense network deployment is a cost efficient solution to offload the traffic over some small cells. The overlapped coverage areas of small cells create more than one candidate access points for one mobile user. Signal strength based user association in IEEE 802.11 results in a significantly unbalanced load distribution among access points. However, the effective bandwidth demand of each user actually differs vastly due to their different preferences for mobile applications. In this paper, we formulate a set of non-linear integer programming models for joint user association control and user demand guarantee problem. In this model, we are trying to maximize the system capacity and guarantee the effective bandwidth demand for each user by soft-association control with a software defined network controller. With the fact of NP-hard complexity of non-linear integer programming solver, we propose a Kernighan Lin Algorithm based graph-partitioning method for a large-scale network. Finally, we evaluated the performance of the proposed algorithm for the edge users with heterogeneous bandwidth demands and mobility scenarios. Simulation results show that the proposed adaptive soft-association control can achieve a better performance than the other two and improves the individual quality of user experience with a little price on system throughput.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권7호
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• pp.2938-2956
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• 2020

Objective image quality assessment (IQA) models have been developed by effective features to imitate the characteristics of human visual system (HVS). Actually, HVS is extremely sensitive to color degradation and complex texture changes. In this paper, we firstly reveal that many existing full reference image quality assessment (FR-IQA) methods can hardly measure the image quality with contrast and masking texture changes. To solve this problem, considering texture masking effect, we proposed a novel FR-IQA method, called Texture and Color Quality Index (TCQI). The proposed method considers both in the masking effect texture and color visual perceptual threshold, which adopts three kinds of features to reflect masking texture, color difference and structural information. Furthermore, random forest (RF) is used to address the drawbacks of existing pooling technologies. Compared with other traditional learning-based tools (support vector regression and neural network), RF can achieve the better prediction performance. Experiments conducted on five large-scale databases demonstrate that our approach is highly consistent with subjective perception, outperforms twelve the state-of-the-art IQA models in terms of prediction accuracy and keeps a moderate computational complexity. The cross database validation also validates our approach achieves the ability to maintain high robustness.

• 한국산학기술학회논문지
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• 제16권4호
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• pp.2656-2664
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• 2015

본 연구는 위암 진단 당시 진단 경로에 따라 병기 및 관련요인의 차이가 있는지 비교하기 위해 시행되었다. 조사대상은 충남대학교 병원에서 위암에 대해 진단 받은 뒤 수술하기 위해 내원한 환자 375명으로 하였으며, 자료 수집은 2010년 8월 1일부터 2013년 3월 31일까지 표준화된 자기기입식 설문지를 사용하여 수집하였다. 증상군과 검진군간에 영향을 미치는 요인의 위험도를 측정하기 위해 로지스틱회귀분석을 사용 하였다. 연구결과, 검진군에서의 조기위암의 비율이 증상군에서 보다 유의하게 높아(p=0.001) 조기검진의 중요성을 시사해 주었다. 또한 증상군은 검진군에 비해 병기가 상대적으로 높았다.(p=0.001). 앞으로 위암 선별검사가 널리 시행되고 대규모의 전향적인 연구가 뒷받침 되면 우리나라에 가장 적절한 검사 및 간격에 대한 추정까지도 가능할 것이다.

• 한국산학기술학회논문지
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• 제16권4호
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• pp.2807-2817
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• 2015

본 연구의 목적은 샌프란시스코시의 HOPE SF 제도를 대상으로 공공임대주택단지 재정비시 커뮤니티에 대한 종합적 재생을 도모한 제도의 내용과 사례를 분석함으로써 국내 제도개선에 시사점을 도출하는데 있다. 그러나 HOPE SF를 통한 단지 재생은 진행형인 점에서 현재 구체적인 결과를 파악하기에 어려움이 있어, 프로그램의 특징 및 내용은 샌프란시스코 시의 공공임대주택제도와 HOPE SF를 연계하여 분석하되 사례의 경우 HOPE SF를 중심으로 살펴봄으로써 정책 변화과정 및 사업 특징을 이해하고자 했다. 본 논문의 결과는 다음과 같다. 첫째, 주민의 모든 단계 참여를 도모하여 재정착을 돕고 커뮤니티의 훼손을 막고자 했다. 둘째, 소득계층 혼합을 통해 주변과 통합적 연계를 유도하였다. 셋째, 주민의 사회경제적 자립과 생활을 위한 실질적 지원을 제공하였다. 넷째, 여러 민관 주체를 연계하여 지역사회의 관심을 환기하였다. 다섯째, 다양한 재정 지원 및 수익창출형 정비 계획을 실시하여 지속가능한 재생을 유도하였다.

• Nutrition Research and Practice
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• 제7권6호
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• pp.510-518
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• 2013

This study aims to demonstrate the effect of farming technology on introducing medicinal plants (MP) and wild food plants (WFP) into a traditional agricultural system within peri-urban zones. Field investigations and semi-structured focus group interviews conducted in the Buhozi community showed that 27 health and nutrition problems dominated in the community, and could be treated with 86 domestic plant species. The selected domestic MP and WFP species were collected in the broad neighboring areas of the Buhozi site, and introduced to the experimental field of beans and maize crops in Buhozi. Among the 86 plants introduced, 37 species are confirmed as having both medicinal and nutritional properties, 47 species with medicinal, and 2 species with nutritional properties. The field is arranged in a way that living hedges made from Tithonia diversifolia provide bio-fertilizers to the plants growing along the hedges. The harvest of farming crops does not disturb the MP or WFP, and vice-versa. After harvesting the integrated plants, the community could gain about 40 times higher income, than from harvesting farming crops only. This kind of field may be used throughout the year, to provide both natural medicines and foods. It may therefore contribute to increasing small-scale crop producers' livelihood, while promoting biodiversity conservation. This model needs to be deeply documented, for further pharmaceutical and nutritional use.

• 한국해안해양공학회지
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• 제10권4호
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• pp.165-173
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• 1998

파고와 주기 그리고 수심의 함수로 정의된 이류계수를 파고와 주기에 대한 결합분포함수와 확률적으로 결합하여 수중둔덕의 이동율을 예측할 수 있는 해석해를 유도하였다. 파랑의 비선형성에 의하여 유발되는 하상에서의 흐름이 표사의 이동을 유발한다는 가정하에 개념적 모형의 표사이동량 방정식을 사용하였다. 표사보존식에 표사이동량을 대입하여 시간에 따른 해저면의 변동을 나타내는 비선형 이류-확산 방정식을 얻을 수 있었다. 해석해에 의하면 수심이 증가할 수록 수중둔덕의 이동율은 지수적으로 감소하는 경향을 보였다. 그러나 스펙트럼에서 주파수 영역의 폭을 정의하는 계수, v의 값이 커지면 수중둔덕의 이동율은 증가하였다. 해석해에 의하여 예측된 수중둔덕의 이동율은 관측자료보다 과대평가하는 경향을 나타내나, 해석해를 유도하는 과정에 내포된 이론식의 제약성 및 입력자료의 부정확성 등을 고려할 때 전반적으로 해석해의 결과는 관측자료와 잘\ulcorner 일치한다고 볼 수 있다. 특히, 수심의 변화에 따른 해석해의 거동은 대상영역 외해에서 추정된 자료를 이용하여 이산화 기법으로 추정된 결과와 매우 잘 일치하였다.

• 대한지역사회영양학회지
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• 제17권6호
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• pp.772-781
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• 2012

In order to supply the reference data to define the quality of life of the rural agricultural elderly population in the simplified steps, the data were collected by personal visits to 232 elder people over 65 (89 males and 143 females) in Sunchang area. The survey was conducted with written questionnaires concerning the quality of life, health-related habits, basic physical functions and cognitive behavior. The prevalence of the degenerative diseases were assessed by anthropometric and biochemical determinations. The averaged overall quality of life represented by EQ-5D index with Nam's model was calculated to be $0.865{\pm}0.1509$, and the percentages of people below the average were 38% (low QOL group) and 62% (high QOL group) were found to be the above the average. Generally, the subjects with male gender, higher educational background, higher self-rated health status, higher social activities were belonged to the high QOL group. The high QOL group had higher scores of daily living activities KADL and IADL, and lower risks in cognitive functions K-MMSE and depression scale GDS. There was no statistically significant correlation between biochemical indexes of blood and cognitive function and EQ-5D scores when the results were adjusted for age and gender. There were significant differences in nutritional assessment determined by the MNA between the high and low QOL groups. The low QOL group showed inferior nutritional status. The rapidly measurable factors of the quality of life of rural elderly were turned out to be physical activity scores and the simplified nutritional status measurement.

• 한국항공우주학회지
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• 제44권4호
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• pp.290-297
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• 2016

사각덕트에서 난류 유동장으로 분사되는 액체 제트의 액주 분열과 미립화 현상에 관한 LES를 수행하였다. 기체상태의 공기 유동 해석에 오일러리안 해법을 사용하고, 액적 추적을 위하여 라그랑지안 해법을 사용하여 기체-액체간 이상유동(two phase flow) 해석을 수행하였다. 액적 분열 모델, 아격자 스케일 모델 및 공간 차분법에 따른 액적 분열을 조사하였다. 액체 제트의 침투깊이를 경험식과 비교하였으며 경험식보다 약간 높음을 알 수 있었다. 제트 후류에서 사우터 평균직경에 대한 분석을 수행하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권9호
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• pp.4467-4486
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• 2018

Trying to deal with the problem of low robustness of Copy-Move Forgery Detection (CMFD) under various transformation and degradation attacks, a novel CMFD method is proposed in this paper. The main advantages of proposed work include: (1) Discrete Analytical Fourier-Mellin Transform (DAFMT) and Locality Sensitive Hashing (LSH) are combined to extract the block features and detect the potential copy-move pairs; (2) The Euclidian distance is incorporated in the pixel variance to filter out the false potential copy-move pairs in the post-verification step. In addition to extracting the effective features of an image block, the DAMFT has the properties of rotation and scale invariance. Unlike the traditional lexicographic sorting method, LSH is robust to the degradations of Gaussian noise and JEPG compression. Because most of the false copy-move pairs locate closely to each other in the spatial domain or are in the homogeneous regions, the Euclidian distance and pixel variance are employed in the post-verification step. After evaluating the proposed method by the precision-recall-$F_1$ model quantitatively based on the Image Manipulation Dataset (IMD) and Copy-Move Hard Dataset (CMHD), our method outperforms Emam et al.'s and Li et al.'s works in the recall and $F_1$ aspects.