• Journal of Pharmaceutical Investigation
• /
• v.21 no.1
• /
• pp.33-41
• /
• 1991

A high-performance liquid chromatographic (HPLC) method was developed for the simultaneous determination of theophylline(TP) and its metabolites, 1-methyluric acid (1-MU) and 1,3-dimethyluric acid (1,3-DMU), in rat plasma and urine. An $100\;{\mu}l$ aliquot of a plasma or urine sample was mixed with $250\;{\mu}l$ of acetonitrite and vortexed. After centrifugation, $200\;{\mu}l$ (plasma) or $20\;{\mu}l$ (urine) aliquot of the supernatant was dried by $N_2$ stream and redissolved in $100\;{\mu}l$ (plasma) or $200\;{\mu}l$ (urine) of the mobile phase. A $20\;{\mu}l$ of the mobile phase solution was injected onto a $C_{18}$ reversed-phase column. The column was maintained at $45^{\circ}C$ by the aid of electric heating jacket. The mobile phase was a 3%(v/v) methanol solution in deionized water which contains sodium acetate (100 mM) and tetrabutyl ammonium hydroxide (4 mM). pH of the mobile phase was adjusted 4.5 by the addition of acetic acid. Detection limits for TP, 1-MU, and 1,3-DMU in plasma were 0.2, 0.1 and $0.1\;{\mu}/ml$, respectively and the corresponding values in urine were all $5\;{\mu}g/ml$. Inter- and intra-day variability of the assay for all compounds in the plasma samples was less than 5.5 and 3.8%, respectively. The retention times for 1-MU, 1,3-DMU, and TP were approximately 7, 8.5 and 18 min, respectively. Sample preparation procedure used in this method was simple, rapid and reproducible. Renal clearance of TP and its metabolites in rats showed plasma concentration dependency indicating renal tubular secretion and reabsorption of them.

• Journal of KIISE:Computer Systems and Theory
• /
• v.33 no.10
• /
• pp.722-733
• /
• 2006

In scalable streaming application, there are two important knobs to tune to effectively exploit the underlying network resource and to maximize the user perceivable quality of service(QoS): layer selection and packet scheduling. In this work, we propose Semantics Aware Packet Scheduling (SAPS) algorithm to address these issues. Using packet dependency graph, SAPS algorithm selects a layer to maximize QoS. We aim at minimizing distortion in selecting layers. In inter-frame coded video streaming, minimizing packet loss does not imply maximizing QoS. In determining the packet transmission schedule, we exploit the fact that significance of each packet loss is different dependent upon its frame type and the position within group of picture(GOP). In SAPS algorithm, each packet is assigned a weight called QoS Impact Factor Transmission schedule is derived based upon weighted smoothing. In simulation experiment, we observed that QOS actually improves when packet loss becomes worse. The simulation results show that the SAPS not only maximizes user perceivable QoS but also minimizes resource requirements.

• The KIPS Transactions:PartD
• /
• v.8D no.1
• /
• pp.10-23
• /
• 2001

Transactions in real-time active databases have the notion of activeness where transactions are generated by external effects and another transaction. In this paper, we propose the multi version concurrency control algorithm for real-time active transactions. A real-time active transaction has a timing constraint in the form of a deadline until which the user wants to complete the transaction, and is characterized by triggering relationships which mean that association between a transaction that triggers the execution of another transaction and the triggered transaction. The triggering relationship is an important factor to resolve data conflicts among real-time active transactions. The proposed concurrency control mechanism resolves data conflicts by considering triggering relationships between conflicting transactions as well as priorities and precedence relationships. The conflict resolution mechanism considers association types of the triggering relationship such as abort and commit dependency, and then resolves data conflicts in favor of higher priority transactions. We also present the experimental results of our algorithm comparing other real-time active concurrency control algorithms.

• Korean Journal of Social Welfare
• /
• v.61 no.4
• /
• pp.137-161
• /
• 2009

In an effort to identify predictors of job performance, research studies in social work administration has been so far on the individual practitioners' levels of knowledge and skills, which could be used in a workplace. As the theoretical concept of organizational environment was fully introduced into social work administration research, however, studies on practitioners' job performance began to have interest in the team or the organizational level variables as well as individual level variables. Along the course of this tendency, this study attempted to test the effect of individual, team, and organizational level variables on the job performance of human service workers. The individual level variables consisted of knowledge, skills, job satisfaction, personality, and counter-productive work behaviors of workers. The team or the organizational level variables included situational constraint, organizational justice, job characteristics, government-dependency, and inter-organizational cooperation. Multi-level complex survey data collected by cluster sampling method from 314 practitioners in 23 organizations were analyzed using Hierarchial Linear Model. Results showed that both task and contextual performance were affected by individual, team, and organizational level variables in various ways.

• Journal of Environmental Policy
• /
• v.9 no.4
• /
• pp.53-76
• /
• 2010

This paper attempts to estimate and compare environmental Kuznets curves (EKC) for$CO_2$ emissions of five regions constituting South Korea. For this, panel data of $CO_2$ emission for these regions are constucted for the period 1990 - 2007. Close inter-dependency among these five regions is considered by using a seemingly unrelated regression (SUR) model. In addition to real per-capita income, price index of energy sources and population dens ity are included as control variables. Results of estimates show the robust existence of EKC's in all these regions. EKC turning points of five regions range between 13.7 and 21.6 million Korean Won, showing a large variation. This difference among regions should be conisidered for the effective implementation of policies targeting the reduction of $CO_2$ emmission. In addition, the increase of energy price is found help reduce the $CO_2$ emmision while the rise of population density seems to lead to the increase of $CO_2$ emission.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
• /
• v.13
• /
• pp.767-804
• /
• 2000

International network strategy is intended to examine the validity of existing network-centered theories in order to ascertain why small-and medium-sized enterprises are useful as a strategic correspondence to the internationalization trend. Small-and medium-sized enterprises can be estimated as being vital majorities in terms of their flexibility to meet changable conditions in international marketing compared with the conglomerates Therefore, their dependency on a few conglomerates for the international economy can be diverged. Generally, the successful internationalization of industries can be derived from the creation of suitable strategies for its competence and quality with the effective correction and completion of its strategy and tactics through mistakes. The internationalization strategy of small-and medium-sized enterprises should not be the reckless pursuit of internationalization that depends only on the increase of investment or the simple induction of the other conglomerates strategic models, but it should be accomplished through the evolution and practice of the concrete strategies that will be more proper for the enterprise's property and efficiency. The results of analyses with proof can be summarized with two effects in large in the process of internationalization of domestic small-and medium-sized enterprises. First, the capacity for internationalization of firms results from a long-term training procedure and continuous development of managing activities. Then in time this becomes an important element for the small-and medium-sized firms in terms with its position targeted international trading. However, the domestic enterprises are showing their abilities in the international competition in quantity, and trying to establish relationships between the enterprises through international networks. Second, statistics might not be meaningful in part because of the lack of data for analysis. It seems that more useful results will be derived from obtaining and utilizing sufficient information and from establishing an inter-relationship between the small-and medium-sized enterprises which are investing in foreign companies.

• Journal of Society of Preventive Korean Medicine
• /
• v.10 no.1
• /
• pp.33-51
• /
• 2006

With the reduction of contagious diseases throughout the world and prolonged life expectancy has lead into increase of habitual related diseases. Industrial development and better economic situation made people more concerned about their health. As primary illnesses are subdued in the past years, health care system and the public value prevention and well-being more than the treatment itself. Based on this trend, this study focused on the view of life from the perspective of Oriental medicine as it's peculiarities, regimen methods, and the definition of healthy life are evaluated. Following results were obtained: - View of life in Oriental medicine focused on two basic principles of interrelationship between the organs internally, inter-dependency with the natural environment and social surrounding externally as recognition and respect between the medium were valued. - Sustaining and maintaining good health in Oriental medicine are closely related to prenatally healthy pregnancy and fetation, as well as prenatal training. Postnatal maintenance includes accommodation to seasonal changes, adequate food intake, mind control, various regimen methods and avoidance of wrong doings. - Defining health includes body's internal condition and external influences, principles of essence, qi, spirit, and yin and yang, harmony and balance, and individuality. - To conclude, good health in Oriental medicine is defined as 'external adaptation to society and natural environment, and internal balancing of individual difference with accumulation of essence, nurturing and circulating qi, and every material around the body in harmony and balance."

• Korean Journal of Social Welfare
• /
• v.64 no.4
• /
• pp.5-29
• /
• 2012

This study aimed to express the experiences of the parents who lost their children by suicides in their own words from their own perspectives by van Manen(2000)'s hermeneutic phenomenological approach. The analysis of the words expressed by the research participants led to the following five fundamental themes. These are 'broken heart, sinner's grief, land of exile and time stood still, pains to be comforted, and days ahead with half-stitched wounds'. Several distinctions are found due to cultural differences from Korean parents. First, whereas the Western parents see the cause of their child's suicide as his/her independent issue, the Korean parents blame themselves entirely. This may have stemmed from the overly inter-dependency between the parents and the child. Second, whereas the Western perspective views the suicide as a type of illness from the individual's depression. The Korean perspective views the suicide as a shame that disgraces the parents or the family. This negative social perspective intensifies the self-blame and social isolation. Third, the Westerners recognize the prevention and responsibility of suicide resting with the society and government, but the Korean society recognize suicide as personal or family matter. Based on the finding above, I proposed a number of practical measures to aid the surviving parents who belong to a group with extremely high suicidal rates.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.40 no.2
• /
• pp.137-144
• /
• 2017

The business process of global third party logistics company is defined as a network of logistics activities which involves the products that are manufactured in the developing countries, such as Vietnam, China and so on, and delivered to North or South American countries via intermediate stopover sites. The third party logistics company usually uses proprietary logistics information system to support the related logistics activities. However, each consignor sometimes may require different business process based on the customer type or characteristics of their products. Therefore, the third party logistics company need to modify their business process to reflect customer's requirements, resulting in the modification of logistic information systems and additional costs. Therefore, a flexible mechanism is required to efficiently support the various types of requirements by the owners of the products. In this paper, first, we figured out various business rules related to third party global logistics activities. Second, we grouped the identified business rules into business processes, objects, relations, dependency, policy, representations, execution, and resources and further into precondition, postcondition, and invariant based on checking point in time. Furthermore, the categorized rules are classified into inter-activity and intra-activity rules based on the execution range. Third, we proposed a rule syntax to describe the defined rules into scripts which are understood by user and information system together. When each activity is executed, the rule manager checks whether there are rules related with the activity execution. Finally, we developed a prototype rule management system to show the feasibility of our proposed methodology and to validate it with an example.

• Journal of KIISE:Computer Systems and Theory
• /
• v.26 no.7
• /
• pp.767-777
• /
• 1999

인과적 메시지 로깅 기법은 정상프로세스를 역전(roll-back)시키거나 메시지의 저장을 위해 프로세스의 수행을 중단시키지 않는 장점을 지니고 있지만, 메시지의 크기가 지나치게 커진다는 단점을 지니고 있다. 본 논문에서는 인과적 메시지 로깅 기법의 이러한 문제점을 해결하기 위하여 로그 상속의 개념을 정의하고 로그 연혁을 이용하여 로그 비용, 특히 로그 크기 면에서 효율적인 로깅 기법을 제안한다. 또한 이 로깅 알고리즘을 이용하여 복구시 메시지의 수와 크기를 줄여 복구시간을 줄이는 효율적인 복구 알고리즘을 제안하고, 제안한 알고리즘이 메시지 로그 크기 면에서 효율적임을 증명한다. 또 제안한 알고리즘의 성능을 검증하기 위하여 두 가지 종류의 모의 실험을 수행하여 기존의 로깅 프로토콜과 메시지 크기 면에서의 성능을 비교한 결과를 제시하였다.Abstract Causal message logging has many good properties such as nonblocking message logging and no rollback propagation. However, it requires a large amount of information to be piggybacked on each message, which may incur severe performance degradation. This paper presents an efficient causal logging algorithm based on the new message log structure, LogOn, which represents the causal inter-process dependency relation with much smaller overhead compared to the existing algorithms. The proposed algorithm is efficient in the sense that it entails no additional information other than LogOn to be carried in each message, while other existing algorithms require extra information other than the message logs. This paper also presents an efficient recovery algorithm to solve the problem of a large amount of data exchanges during the recovery. To verify the performance of our algorithm, we give an analysis of the algorithm and perform two simulations and compare the log size with other causal logging protocols.