• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.607-608
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• 2008

Locking time of the DLL is the important design issue in case of clock gating for low power system. For precise analysis of the locking speed of the DLL, this paper analyzes the locking process of the DLL in time domain. Analysis result shows that the value of the DLL bandwidth over reference frequency should be limited to below 1 ($i.e.w_n/F_{REF}<1$) for the stable operation and relation between bandwidth and lock time is expressed by log function.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.427-432
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• 2003

An analytical method to predict the flexural behavior of composite girder is presented in which the early-age properties of concrete are specified including maturing of elastic modulus, creep and shrinkage. The time dependent constitutive relation accounting for the early-age concrete properties is derived in an incremental format by expanding the total form of stress-strain relation by the first order Taylor series with respect to the reference time. The sectional analysis calculates the axial and curvature strains based on the force and moment equilibriums. The deflection curve of the box girder approximated by the quadratic polynomial function is calculated by applying to the proper boundary conditions in the consecutive segments. Numerical applications are made for the 3-span double composite steel box girders which is a composite bridge girder filled with concrete at the bottom of the steel box in the negative moment region. The one dimensional finite element analysis results are compared with those of the three dimensional finite element analysis and the analytical method based on the sectional analysis. Close agreement is observed among the three methods.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.463-468
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• 2003

A finite element formulation to predict the flexural behavior of composite girder is presented in which the early-age properties of concrete are specified including maturing of elastic modulus, creep and shrinkage. The time dependent constitutive relation accounting for the early-age concrete properties is derived in an incremental format by expanding the total form of stress-strain relation by the first order Taylor series with respect to the reference time. The total potential energy of the flexural composite member is minimized to derive the time dependent finite element equilibrium equation. Numerical applications are made for the 3-span double composite steel box girders which is a composite bridge girder filled with concrete at the bottom of the steel box in the negative moment region. The numerical analysis with considering the variation of concrete elastic modulus are performed to investigate the effect of it on the early-age behavior of composite structures. The one dimensional finite element analysis results are compared with the analytical method based on the sectional analysis. Close agreement is observed among the two methods.

• Journal of Korea Society of Digital Industry and Information Management
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• v.12 no.4
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• pp.71-79
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• 2016

This study proposes a performance model of a shared bus multi-processor system and analyzes the effect of input/output types on system performance and overload of shared resources. This system performance model reflects the memory reference time in relation to the effect of input/output types on shared resources and the input/output processing time in relation to the input/output processor, disk buffer, and device standby places. In addition, it demonstrates the contribution of input/output types to system performance for comprehensive analysis of system performance. As the concept of workload in the probability theory and the presented model are utilized, the result of operating and analyzing the model in various conditions of processor capability, cache miss ratio, page fault ratio, disk buffer hit ratio (input/output processor and controller), memory access time, and input/output block size. A simulation is conducted to verify the analysis result.

• Journal of Information Technology Services
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• v.7 no.2
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• pp.25-39
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• 2008

As the amount of IT investment and the complexity of information systems in public agencies have been increased, efficient and structured management of IT systems is more emphasized. For the Korean government. ITA (Information Technology Architecture) is one of the core parts of the e-Government initiative. Also introducing and managing ITA in organizations is mandated by law in Korea. The objective of the paper is to study whether using ITA in public agencies is related with their IT capability and IT performance or not. A questionnaire had been designed for the purpose, and a survey had been performed on Korean public agencies. The survey results show that using ITA has influence on relation and technology capability. However, ITA does not influence on human capability and IT performance. The reason why using ITA is linked to relation and technology capability is that ITA includes relationship between both business and technology. Also ITA provides a technical reference model (TRM) and standard profile (SP), so it has influence on technology capability.

• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.49-51
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• 2004

The iron loss in electric machines takes large part of machine losses and the reduction of iron loss brings the increase of the efficiency. In the rotating machines, however it is very difficult to calculate the iron loss and to get the exact experiment result because the measuring precesses are very complex and laborious. As is well known, the relation between the flux density B and the magnetic field intensity H relation is not linear. For the iron loss, B and H must be measured and usually B becomes the reference wave(sine wave) and the following H is measured using H-coil. To make the B as sine wave, B is controlled by some devices. The error is controlled to become zero by the proposed algorithm which uses the bisection algorithm. The experiments are compared with the simulation results, and they show acceptable agreements.

• SUVANNABHUMI
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• v.10 no.1
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• pp.93-116
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• 2018

Under feudalism, besides imploring investiture, tribute is said to be one of the two most typical activities at the core of diplomatic relations between China and the region, in particular, Vietnam and Japan. By using the comparative method and interdisciplinary approach, the author shows that there are many differences between Vietnam and Japan with regards to tribute activity with China during the feudal period. For example, the start and end of China's tributary activities with Vietnam and Japan are not the same. The period of Japanese tributary activity was much more loosened than Vietnam. Vietnamese tributary relation was political, while Japan placed economic benefits as the main priority. In particular, the author also proved that although Japan and China had differences in behavior and level of dependence on the tributary activity of Vietnam, both Vietnam and Japan maintained independence and autonomy. Based on the historical, cultural, and geographical characteristics, as well as the position and force correlation of each country in relation to China, this article also explains the causes of these similarities and differences.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.21 no.2
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• pp.81-96
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• 2010

This study aimed to suggest metadata elements for online reference resource systems based on users' perceptions. We surveyed librarians in four types of libraries, asking them indicate the need for each of 17 metadata elements. The survey results were compared to the current data input rates of the system, which has been operating for the past two years. Based on both the respondent data and current data input rates, we suggested that title, description, subject, creator, type, identifier, language, coverage, location, and tag elements must be included in the system as the metadata elements for online reference resources. n addition, the input rates of creator and copyright were 20.20% and 18.30%, respectively, but the respondents answered that these items were needed 82.15% and 82.77%, respectively. Therefore, these two items are necessary as metadata elements. On the other hand, the data input rates of type, source, date, relation, and contribution were less than 3%, but almost 70% of respondents answered that all these items were needed. So further research should be performed to determine whether or not these items are needed for online reference resource systems.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.2
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• pp.109-118
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• 2016

Objectives: To review reference levels by the international and domestic management and provide the basis for setting occupational exposure limits(OELs) of radon in Korea Methods: Government's organizations with laws and systems for monitoring radon exposure were investigated and compared. There are five laws governing Indoor Air Quality(IAQ) control such as Occupational Safety and Health Act, Indoor Air Quality Control in Public Use Facilities, Etc. Act, School Health Act, Public Health Control Act and Parking Lot Act in Korea. It was surveyed that a total of 32 countries including 24 countries in the European Union(EU), six countries in Asian and two countries in North America setting the reference levels for radon in the world. Results: In Korea, there are set guidelines for radon in the Ministry of Environment and the Ministry of Education. Reference levels of radon for existing dwellings were $150{\sim}400Bq/m^3$ for Western European countries, and $200{\sim}1,500Bq/m^3$ in Eastern European countries. Approximately 67% of those EU countries were set up $400Bq/m^3$ to the standards for existing dwellings. EU countries such as Luxembourg, Finland, Norway, Sweden and Russia had adopted mandatory level for radon. Radon guidelines for new dwellings were set more strictly reference level($200Bq/m^3$) than existing dwellings. Conclusions: International organizations such as ICRP, UNSCEAR and NCRP, etc. had recommended the guidelines for radon. It was calculated the relation of the dose conversion factors with the annual effective doses. the OELs of radon suggest to need to establish $150Bq/m^3$ for office room and $400{\sim}1,000Bq/m^3$ for the workplace.

• Korean Journal of Computational Design and Engineering
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• v.21 no.4
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• pp.433-442
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• 2016

This paper aims to define the relational logic of in-between code articles as well as within atomic sentences in Korean Building Code, as an intermediate research and development process for the automated building permit system of Korea. The approach depicted in this paper enables the software developers to figure out the logical relations in order to compose KBimCode and its databases. KBimCode is a computer-readable form of Korean Building Code sentences based on a logic rule-based mechanism. Two types of relational logic definition are described in this paper. First type is a logic definition of relation between code sentences. Due to the complexity of Korean Building code structure that consists of decree, regulation or ordinance, an intensive analysis of sentence relations has been performed. Code sentences have a relation based on delegation or reference each other. Another type is a relational logic definition in a code sentence based on translated atomic sentence(TAS) which is an explicit form of atomic sentence(AS). The analysis has been performed because the natural language has intrinsic ambiguity which hinders interpreting embedded meaning of Building Code. Thus, both analyses have been conducted for capturing accurate meaning of building permit-related requirements as a part of the logic rule-based mechanism.