위치 기반 서비스에서 도로 네트워크의 거리 정보를 이용한 사용자 정보 은닉 기법

김형일,신영성,장재우,Kim, Hyeong Il,Shin, Young Sung,Chang, Jae Woo 한국공간정보학회 2012 한국공간정보학회지 Vol.20 No.5

최근 PDA, 휴대폰과 같은 모바일 기기 및 GPS와 같은 무선 통신 기술의 발달로 인하여 위치 기반 서비스의 이용이 확산되었다. 하지만 이러한 서비스는 사용자가 도로 네트워크에서 이동하면서 자신의 위치정보를 통해 LBS 서버에 질의를 요청하기 때문에, 심각한 개인 정보 누출의 위협이 될 수 있다. 따라서 모바일 사용자의 안전하고 편리한 위치기반 서비스 사용을 위한 개인 정보 보호 기법이 필요하다. 이를 위해 본 논문에서는 위치 기반 서비스에서 사용자 정보 보호를 지원하는 도로 네트워크 거리 기반 클로킹 기법을 제안한다. 제안하는 기법은 도로 네트워크에서 효율적이고 안전한 위치기반 서비스를 지원하기 위하여, 도로 네트워크의 거리를 고려하여 클로킹 영역을 설정한다. 아울러, 성능평가를 통해서 제안하는 기법이 클로킹 영역 및 서비스 시간 측면에서 기존 연구보다 우수함을 보인다. Recent development in wireless communication technology like GPS as well as mobile equipments like PDA and cellular phone makes location-based services (LBSs) popular. However, because users request a query to LBS servers by using their exact locations while moving on the road network, users' privacy may not be protected in the LBSs. Therefore, a mechanism for users' privacy protection is required for the safe and comfortable use of LBSs by mobile users. For this, we, in this paper, propose a road network distance based cloaking scheme supporting user privacy protection in location-based services. The proposed scheme creates a cloaking area by considering road network distance, in order to support the efficient and safe LBSs on the road network. Finally, we show from our performance analysis that our cloaking scheme outperforms the existing cloaking scheme in terms of cloaking area and service time.

치과용 저금합금과 시효경화

김형일,Kim, Hyeong-Il 대한치과의사협회 1996 대한치과의사협회지 Vol.34 No.9

A Study on the Bit Error Probability of PC/FM System

김형일,김영균,이충웅,Kim, Hyeong-Il,Kim, Yeong-Gyun,Lee, Chung-Ung The Institute of Electronics and Information Engin 1983 전자공학회지 Vol.20 No.2

본 논문에서는 PCM/FM시스템에 대한 비트(bit)오차 확률식을 구하여 이를 수치적으로 계산하여 검토를 행했다. 변조전 필터를 거친 NRZ-L 이진 펄스예을 변조 신호로 하여 반송파를 주파수 변조하였고, 리미터와 변별기를 검출기로 이용하였다. RF 스펙트럼의 제한과 비트 오차 확률의 감소면에서 볼 때, 주파수 편이화 h를 3WT가 되도록 설계하는 것이 적당함을 알 수 있었다. 여기서 W는 변조전 필터의 대역폭이고 T는 한 비트당 시간 간폭이다. The bit error probability of PCM/FM system was derived and numerically calculated. Binary NRZ-L baseband signal was premodulation filtered to frequency modulate a sinusoidal carrier, and a common circuit of limiter-discriminator was employed as a detector. Considering both RF spectrum limitation and bit error Probability reduction, it was found that h ≒ 3WT would be reasonable, where h is the frequency deviation ratio, W is the bandwidth of a premodulation filter and T is the time interval of one bit.

P2P 환경의 위치 기반 서비스에서 연속적인 질의 처리를 지원하는 그리드 기반 Cloaking 영역 설정 기법

김형일,이아름,장재우,Kim, Hyeong-Il,Lee, Ah-Reum,Chang, Jae-Woo 대한공간정보학회 2010 한국공간정보학회지 Vol.18 No.3

Recent development in wireless communication technology, like GPS, and mobile equipments, like PDA and cellular phone, make location-based services (LBSs) popular. However, because, users continuously request a query to a server in the LBSs by using their exact locations, privacy information could be in danger. Therefore, a mechanism for users' privacy protection is required for the safe and comfortable use of LBSs by mobile users. For this, we, in this paper, propose a grid-based cloaking area creation scheme supporting continuous LBSs in peer-to-peer environment. The proposed scheme creates a cloaking area by using Chord protocol, so as to support the continuous LBSs in peer-to-peer environment. Finally, we show from a performance analysis that our cloaking scheme outperforms the existing cloaking schemes, in terms of service time. 최근 PDA, 휴대폰과 같은 모바일 기기 및 GPS와 같은 무선 통신 기술의 발달로 인하여 위치 기반 서비스의 이용이 확산되었다. 하지만 이러한 서비스는 사용자의 정확한 위치정보를 가지고 LBS 서버에 연속적으로 질의를 요청하기 때문에, 심각한 개인 정보 누출의 위협이 될 수 있다. 따라서 모바일 사용자의 안전하고 편리한 위치기반 서비스 사용을 위한 개인 정보 보호 방법이 필요하다. 이를 위해 본 논문에서는 Peer-to-Peer 환경의 위치기반 서비스에서 연속적인 질의 처리를 지원하는 그리드 기반 클로킹(Cloaking) 영역 설정 기법을 제안한다. 제안하는 기법은 Peer-to-Peer 환경에서 연속적인 위치기반 서비스를 지원하기 위하여, Chord 프로토콜을 사용하여 클로킹 영역을 설정한다. 마지막으로 성능평가를 통해서 제안하는 기법이 서비스 시간면에서 기존 연구보다 우수함을 보인다.

특급 호텔 조리사의 근무스케줄이 일-가족갈등 및 직무만족에 미치는 영향

김형일 ( Kim Hyeong Il ),김규석 ( Kim Gyu Seok ),고영욱 ( Ko Young Wook ) 한국호텔리조트학회(구 한국호텔리조트카지노산학학회) 2016 호텔리조트연구 Vol.15 No.3

The purpose of this study is to investigate the effect of luxury hotel chef``s working schedule on work-family conflict and job satisfaction centering around the working schedule satisfied, and to present an alteration and a desirable direction of improvement. Preliminary survey was carried out with luxury hotel chefs in downtown Seoul and Incheon from September 01 to 30, 2015. Total 350 questionnaires were distributed and 337 were recollected, among them 313 excluding unfaithfully answered ones were used as samples. Empirical analysis was carried out based on the collected data using SPSS 18.0 statistical program. Carried out to grasp demographical statistics were technical and statistical analysis, frequency analysis, factor analysis, reliability analysis, multiple regression analysis. In hotel scene, working schedule is set up with the date the person in question wants and the time for chefs`` personal development(schooling, lecture) is used enough. Chefs who have extra- work income showed a higher degree of satisfaction with working schedule. The satisfaction with working schedule raises job satisfaction that enables better service. A better working environment is desirable with working schedule managed and run efficiently and by improving chefs`` job satisfaction.

데이터 접근 패턴 은닉을 지원하는 암호화 인덱스 기반 kNN 질의처리 알고리즘

김형일(Hyeong-Il Kim),김형진(Hyeong-Jin Kim),신영성(Youngsung Shin),장재우(Jae-woo Chang) Korean Institute of Information Scientists and Eng 2016 정보과학회논문지 Vol.43 No.12

In outsourced databases, the cloud provides an authorized user with querying services on the outsourced database. However, sensitive data, such as financial or medical records, should be encrypted before being outsourced to the cloud. Meanwhile, k-Nearest Neighbor (kNN) query is the typical query type which is widely used in many fields and the result of the kNN query is closely related to the interest and preference of the user. Therefore, studies on secure kNN query processing algorithms that preserve both the data privacy and the query privacy have been proposed. However, existing algorithms either suffer from high computation cost or leak data access patterns because retrieved index nodes and query results are disclosed. To solve these problems, in this paper we propose a new kNN query processing algorithm on the encrypted database. Our algorithm preserves both data privacy and query privacy. It also hides data access patterns while supporting efficient query processing. To achieve this, we devise an encrypted index search scheme which can perform data filtering without revealing data access patterns. Through the performance analysis, we verify that our proposed algorithm shows better performance than the existing algorithms in terms of query processing times.

호텔 중간 관리자의 리더십유형과 종사원의 개인특성이 조직시민행동에 미치는 영향

김형일 ( Hyeong Il Kim ) 한국호텔리조트학회(구 한국호텔리조트카지노산학학회) 2013 호텔리조트연구 Vol.12 No.3

This study identified leadership type of hotel middle managers, transformational leadership, transactional leadership on organizational citizenship behavior Antecedents and also on the personal characteristics in relation to the type of leadership and organizational citizenship behavior, and the moderating effects by verifying gave open the way to seek ways to promote organizational citizenship behavior, my hotel in the middle of the improvement and change through a variety of management approaches, in that academic contribution, as well as from the practical point of view, hotel development in effective human resource management was to provide useful information. Oct. 10, 2012 - Oct. 20, 2012 to the sample to estimate the population and limited staff for the attainment of the objectives of this study population was non-probability sampling method, sampling method, which is one of convenience sampling was done. Survey of how to proceed with a direct way to fill in the questionnaire survey respondents by trained investigators adopted. Questionnaire except insincere responses and central tendency of these questionnaires has been reclaimed by hotel employees, deploy a total of 350 questionnaires, 321 questionnaires were used to analyze the 311 call.

분산 병렬 질의 처리를 지원하는 CUBRID 기반 미들웨어 개발

김형일 ( Hyeong-il Kim ),윤민 ( Min Yoon ),조아라 ( Ahra Cho ),최문철 ( Mun-chul Choi ),장재우 ( Jae-woo Chang ) 한국정보처리학회 2014 한국정보처리학회 학술대회논문집 Vol.21 No.2

최근 SNS의 발전으로 인헤 정보의 양이 급격히 증가하였으며,이에 따라 빅데이터 처리를 위한 NoSQL에 대한 연구가 활발히 진행되고 있다. 그러나 NoSQL은 데이터베이스의 ACID 조건을 만족하 지 못하는 문제점이 존재한다. 따라서 RDBMS를 기반으로 빅데이터 처리를 수행하는 연구가 활발히 진행되고 있다. 이를 위한 대표적인 기법인 CUBRID Shard는 데이터베이스를 Shard 단위로 수평 분할하여 각기 다른 물리 노드에 데이터를 분산 저장한다. 그러나 해당 기법은 한 클라이언트의 질의가 다수의 서버에서 실행되어야 하는 경우를 에는 질의를 처리하지 못하는 단점을 보인다. 따라서 본 논문에서는 병렬질의 처리를 지원하는 CUBRID 기반 분산 미들웨어를 제안한다.

베이커리 종사자의 직업성 천식 및 비염이 직무 성과와 이직 의도에 미치는 영향

김형일(Hyeong Il Kim),이은준(Eun Jun Lee),최성기(Seong Gi Choi) 한국조리학회 2010 한국조리학회지 Vol.16 No.5

This study investigates the effects of occupational asthma and rhinitis on job performance in order to maintain the health of bakery workers and to increase manufacturing productivity. Hotel bakery workers, small bakery businesses, bakery franchises and bakeries in large discount stores, located in Seoul, Kyungki and Incheon were sampled for the study over the period of December 1 to 15, 2008. A total of 245 samples were used for the final analysis. To verify the hypothesis established for the study, we conducted frequency analysis, factorial analysis, reliability analysis, correlation analysis and regression analysis using SPSS 12.0, a statistical package, to derive a conclusion. As a result of this study, it turned out that occupational asthma and rhinitis in bakery workers does affect job performance as well as motivating the intention to quit job. It is recommended that in order to increase the job performance of bakery workers and reduce their desire to quit job, their work environment should be improved and that training about occupational asthma and rhinitis should be provided for the prevention and reduction of disease.

베이커리 종사자의 업무특성에 따른 호흡기질환 연구

김형일 ( Hyeong Il Kim ) 한국호텔리조트학회(구 한국호텔리조트카지노산학학회) 2011 호텔리조트연구 Vol.10 No.2

Flour is the basic ingredient for baking. It is well known to cause a respiratory disease all over the world, besides, it is related to respiratory disease of bakery employees. On this paper, the investigation of their respiratory disease will be presented based on various workplaces of bakeries. this paper will be discussed about how this particular disease can be studied and how the environment of the workplace can be improved. Basically, questionnaires are distributed and collected to five-star 6 hotels, 20 bakeries in department stores and 30 private bakeries located in Seoul and Inchon in 2009, 1st of Sep. All of collected questionaries are analyzed through the data-recording process and SPSS12.0. The methods of the analysis to this paper consist of descriptive statistics, the frequency statstics, t-test, and ANOVA in order to grasp accurate date and characters in common. In case there is a tiny difference in result of it, Duncan`s verification takes post censhorship. According to result of this paper, there are 25% of bakery employees who have vocational asthma symptoms, and 40% of vocational rhinitis in a difficult situation. In order to improve efficiency of one`s work load or business, there must be an appeasement policy to prevent vocational asthma symptoms, and vocational rhinitis in bakery workplaces.