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.

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.

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.

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.

K-Pop 댄스 하지동작의 생체역학적 남녀 차이 분석

장영관,홍수연,기재석,장인영,Jang, Young-Kwan,Hong, Su-Yeon,Ki, Jae-sug,Jang, In-Young 대한안전경영과학회 2017 대한안전경영과학회지 Vol.19 No.1

The purpose of this study was to investigate the biomechanical of K-Pop dance movement. The study was conducted on 15 male and 15 female subjects in 20-30 age groups. And they choose 150 K-Pop dance choreographies in the top 10 ranking of the main charts. We analyzed the RoM, joint moment and impulse force of the highlight movements. First, During the K-Pop dance motion, the usage of knee joints are more than the hip joints and the ankle joints, and female dancers has a larger range of motion than the male dancers. Second, male dancer uses more than female dancers when they compared the load of male dancers and female dancers. In particular, flexion and extension of the hip joints are mostly used in this study. Third, the impulse force of male dancers was greater than of female dancers, but it was statistically insignificant, this is equal to the impulse on walking. In conclusion, Female dancers use more range of motion than male dancers, but male dancer choreography requires greater torque, which can strain joints. Most choreographic exercises involve movements such as hip joint, knee joint, flexion of ankle joint, extension, rotation, and jumping.

Gait Stability in K-pop Professional Dancers

장영관,장인영,홍수연 한국운동역학회 2016 한국운동역학회지 Vol.26 No.4

Objective: The purpose of this study was to provide data on gait characteristics of K-pop professional dancers. Method: Participants were divided into four groups: male dancers (n=10, age: 28.2 ± 3.4 years, height: 175 ± 6 cm, weight: 68.9 ± 5.6 kg), female dancers (n=10, age: 26.7 ± 3.1 years, height: 162 ± 4 cm, weight: 52.1 ± 3.7 kg), non-dancer males (n=10, age: 25.2 ± 2.6 years, height: 171 ± 6 cm, weight: 66.4 ± 5.3 kg), or non-dancer females (n=10, age: 26.2 ± 3.0 years, height: 161 ± 5 cm, weight: 56.4 ± 6.7 kg). Twelve infrared cameras (Qualisys, Oqus 500, Sweden, 150 Hz.) were used to capture three-dimensional motion data. Gait motion data of professional dancers and ordinary persons were obtained. Results: K-pop dancers' dynamic stability during the female toe off event and the male heel contact event was better compared with that of ordinary persons in the front-rear direction. In addition, the results showed a significant difference in the margin of stability (MoS). However, the medial-lateral direction of both female and male dancers during heel contact and the toe off event was more stable compared with ordinary person, who exhibited an increased MoS than did the dancers. Conclusion: This study aimed to investigate the gait characteristics of K-pop professional dancers in comparison with ordinary persons using gait parameters and MoS. The stability of K-pop professional dancers' dynamic gait in the front-rear direction was better than that in the medial-lateral direction. Therefore, further studies in which the dance movements of K-pop dancers are sub-divided and analyzed will be necessary to reduce related injury.

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.

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.

관계형 데이타베이스에서 비정규화를 고려한 최적 데이타베이스

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

관계형 데이터베이스에서 응답시간에 제약이 있는 경우 최적 역정규화

장영관 한국산업경영시스템학회 2002 한국산업경영시스템학회 학술대회 Vol.2002 No.추계

Databases are central to business information systems and RDBMS is most widely used for the database system. Normalization was designed to control 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 for processing each select, insert, update, delete transaction, and for treating anomalies. A branch and bound method is proposed for this model.