관계형 데이타베이스에서 비정규화를 사용한 데이타베이스 설계

장영관,강맹규 한국경영과학회 1996 한국경영과학회 학술대회논문집 Vol.- No.1

Databases are critical to business information systems, and RDBMS is most widely used for the database system. Normalization has bees designed to control various anomalies(insert, update, and delete anomalies). However, normalized database design does not account for the tradeoffs necessary for the performance. In this research, we develop a model for database design by denormalization of duplicating attributes in order to reduce frequent join processes. In this model, we consider insert, update, and delete costs. The anomalies are treated by additional disk I/O which is necessary for each insert and update transaction. We propose a branch and bound method for this model, and show considerable cost reduction.

관계형 데이터베이스에서 비정규화를 고려한 최적 데이터베이스 설계

장영관,강맹규 한국데이타베이스학회 1996 Journal of information technology applications & m Vol.3 No.1

Databases are critical to business information systems, and RDBMS is most widely used for the database system. Normalization has been designed to control various anomalies(insert, update, and delete anomalies). However, normalized database design does not account for the tradeoffs necessary for the performance. In this research, we develop a model for database design by denormalization of duplicating attributes in order to reduce frequent join processes. In this mood, we consider insert, update, delete, and query costs. The anomaly and data inconsistency are removed by additional disk I/O which is necessary for each update and insert transaction. We propose a branch and bound method for this model, and show considerable cost reduction.

초등학생 스마트폰 사용 유ㆍ무 보행의 신체움직임 기능 차이

장영관,신학수,장인영,홍수연,공세진,정왕수,하종규 대한안전경영과학회 2015 대한안전경영과학회지 Vol.17 No.4

The purpose of this study was to investigate temporal and spatial variations, and moments of the lower extremities of gait while playing the game with smartphone under different curb-heights. Ten male elementary school students(from 10 years to 13 years old) participated in this study. Twelve infrared cameras(Oqus-500) and two force plates(9260AA) were used for collecting data and these were processed via Visual 3D software. In conclusion, with or without smartphone and with different curb-heights, the spatial and temporal parameters of walking were not the same and coefficients of variations were not consistent. The maximum joint moments of the lower extremities with or without smartphone were not statistically significant but those of hip and ankle joint were statistically significant with regard to the different heights of the curbs.

K-Pop 댄스 수준에 따른 근활성도 및 운동역학적 에너지 비교 분석

장영관,홍수연,김진현 한국스포츠학회 2016 한국스포츠학회지 Vol.14 No.1

The purpose of this study was to compare Biomechanical energy and muscle activation analysis of according to K-Pop dance level. Thirteen subjects(5 men, 8 women) who K-Pop dance professional choreographer were participated in this study. We divided 40 dance song 2 groups: level 1 (26.4±2.85kcal), level 2(49.65±5.53) based on of energy consumption. In order to measure muscle activity, the delsys (USA) was used. Seven muscles (biceps brachii, triceps brachii, rectus abdominis, rectus femoris, biceps femoris, tibialis anterior, gastrocnemius) activation were analyzed. As a result, Muscle Activity of all the segment does not affect the energy consumption. but, Depending on level, biceps femoris muscle activities were significantly different. Second, mechanical energy and energy consumption has an effect to each other. Third, Level 2 used more mechanical energy than the level 1. And according to level, potential energy, rotation energy and kinetic energy showed statistical different.

K-Pop 댄스 동작의 생체역학적 패턴 분석

장영관,홍수연,정왕수 한국스포츠학회 2015 한국스포츠학회지 Vol.13 No.4

The purpose of this study was to quantify and analyze the biomechanical data of K-Pop dance. A professional choreographer who was GD & TOP HIGH HIGH dance participated in this study. As a result, jump twice were repeatedly reduced time in jump phase. The COM velocity of first jump was greater in every direction than second jump. The flexion and extension max moment of Second phase of Hip and knee joint were the greater than other joint. hip joint and knee joint external rotation was reduced. All right foot four jumps were decreased time as repeated jump in every sections. CoM position of first section jump was large change than the other section.

관계형 데이터베이스의 성능 향상 방법

장영관 三陟大學校 産業科學技術硏究所 2002 産業科學技術硏究論文集 Vol.7 No.3

The relational database management system (RDBMS) is the most popluar database management system in use today. In RDBMS, as in any large and complicated system, performance is key issue. One of the biggest responsibilities of a DBA is to ensure that the Oracle database is tuned properly. It's an issue that we need to deal with ongoing basis, through all the stages of system's life cycle: from planning to design to programming to testing to production. Problems for improving performance of database never stops. Even after a system is in production, DBA need to keep monitoring and tuning and improving it as time and circumstances change. This paper presents the performance improvement method of relational database that is adaptable from the initial design phase, to the life of database system.

최단 경로 문제를 위한 데이터 구조 설계

장영관 三陟大學校 1998 論文集 Vol.31 No.2

Shortest path algorithm is most effective method in solving transportation problem, OR, etc. Algorithm and data structure is unsuitable, the algorithm becomes inefficiently. In this research, I propose efficient data structure for Kijkstra algorithm. The proposed design is consisted in node list and arc list. Kijkstra algorithm becones most effective by using the proposed data structure. The reason of effectiveness is the ability of using binary search method in solving the algorithm. Because the complexity of binary search method is log₂N, the proposed data structure ismost effective in implementing Kijkstra algorithm.

관계형 데이터베이스의 역정규화 문제를 위한 발견적 기법

장영관 三陟大學校 産業科學技術硏究所 2002 産業科學技術硏究論文集 Vol.7 No.2

The process of normalization was intoroduced with the purpose of improving database design, by not allowing anomalies to occur. Normalized relations provide an appropriate logical structure for database design, eapecially when given in third normal form. However, normalized database design does not account for the tradeoffs necessary for performance. In this research, we model a database design method considering denormalization of duplicating attributes in order to reduce frequent join processes. This model considers insert, update, delete costs and anomalies are treated by additional disk I/O necessary for each insert, update transaction. The proposed model is NP-complete problem with complexity of O(2^n). In this research, a heuristic method is proposed for this model.

체계적 탈정규화 방법

장영관 三陟大學校 1998 論文集 Vol.31 No.2

Databases are critical to business information systems, and RDBMS is most widely used for database systems. Normalization has been designed to control various anomalies(insert, update, and delete anomalies). However, the normalized database design does not account for the trade-offs necessary for a better performance. In this research, we propose a denormalization method for improving performance of relational databases. The proposes method duplicates attributes of a referenced table into a referencing table in order to reduce frequent join processes. With this method, the insert and delete anomalies do not occur, and the update anomaly can be removed completely by a method such as the database trigger. Unlike other methods that are applicable for special cases, the proposed method is applicable for general cases, because it is not influenced by business rule or the semantic meaning of attribute. Our systematic method that takes advantage of referential integrity constraint can be easily used in not only initial database design, but also in redesign of the database under working.

응답시간 제약을 고려한 관계형데이터베이스의 역정규화 방법

장영관 三陟大學校 産業科學技術硏究所 2002 産業科學技術硏究論文集 Vol.7 No.4

Database are central to business information systems and RDBMS is most widely used for the database system. To make database have desirable properties, normalization is used. Normalized databases remove various anomalies (insert, update, delete anomalies). However, normalized database design does not account for the tradeoffs necessary for performance. In this research, we model a database design method considering denormalization of duplicating attributes in order to reduce frequent join processes. This model considers response time constraint for processing each select, insert, update, delete transaction, and for treating anomalies. A heuristic method is proposed for this model.