• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.518-519
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• 2006

A connection between pulse-periodical laser radiation power and stability of liquid-metal contacts between powder particles during selective laser sintering (SLS) is determined based on analysis solving the problem of stability of liquid column in the gravity and capillary forces field. On the grounds of obtained relationships the optimization of pulse-periodical laser radiation power and SLS-process duration is realized, that allows to produce voluminous powder porous materials with pre-determined physical and mechanical properties and surface geometry. Results of metallographic investigations of powder porous materials of titanium powder produced with technological regimes calculated by means of obtained relationships are given in the work

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.211-214
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• 1999

Periodical surfaces with the sawtooth profile are studied on their backscattering by the TE plane wave incident. The backscattering is calculated by the mode-matching method. The surfaces are perfect conductor and are covered with dielectric materials to make a flat surface. It is observed that a cover filled with multiple dielectric layers can be used to reduce the backscattering at an arbitrary incident angle.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.8 no.1
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• pp.157-178
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• 1997

1. Only 6 libraries(23.1%) among 26 surveyed libraries have a person or part in charge of continuing education. It means that the method to select education program and education object is systemless. The 19 libraries (73.1%) encourage continuing education of librarian. 2. Compared with the group who didn't receive a formal education, the group who received have a high degree in the grade of confidence, self-satisfaction and ability for job in Internet education case. And the group that received a formal education have also a high degree in the grade of ability for job in OA education case. Confidence, self-satisfaction for job in the carreer is significantly different according to the formal education in Internet education case and OA education case. Confidence, self-satisfaction and ability for Sob in the scholarship are significantly different according to the formal education in internet and computer OA education case 3. Compared with the group that didn't receive periodical education the group that received periodical education have a high degree in the grade of confidence, self-satisfaction for Job in internet education case. Confidence, self-satisfaction and ability for job in the carreer are significantly different according to the periodical education in OA education case. Confidence, self-satisfaction and ability for businessin in the scholarship are significantly different according to the periodical education in internet and OA education case. 4. Compared with the group that didn't receive self-education the group that received self-education have a high degree in the grade of confidence, self-satisfaction and ability for job in internet and OA education case. Confidence, self-satisfaction and ability for Job in the carreer are significantly different according to the self education in internet and OA education case. Confidence, self-satisfaction and ability for Job in the scholarship are significantly different according to the self-education in internet and OA education case.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.1
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• pp.120-128
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• 2011

Recently, safety diagnosis of the existing structures has been emerged as important issue. In particular, systematical and precise safety diagnostics for steel structures for power substation, have been required. Steel structures for power substation are under the periodical impact loads from operations of gas insulated switchgear. These loading condition accelerates damage and aging of structure. The objective of this research is to evaluate damage of structure under periodical impact loads. To evaluate the integrity of structures as organizing mathematical models including the dynamic characteristics of structures, Frequency Domain Decomposition method was choiced and an algorism was proposed. For verifying this methods and algorism, a mathematical model is composed of the development of a variety of reverse analysis and a signal processing technology reflecting physical damage of structures. A series of analysis and test results indicatge that proposed method has a confidence for applying a filed test. Therefore, it is expected to be able to take advantage of system identification to detect damage for the maintenance and management of steel structures under periodical impact loads such as power substation.

• Journal of the Korean Institute of Rural Architecture
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• v.17 no.3
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• pp.1-9
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• 2015

The purpose of this paper is to analysis on periodical changes of rural houses of Korean-Chinese people residing in Yanbian area, China focused on periodical changes of floor plans according to Chinese government's policies and regulations influencing on rural houses. Changes of floor plans are classified into four periods; immigrating settled period, 1960-1970s, 1980-1990s, and after 2000. Total number of 67 cases were analyzed that data was collected 48 cases of literature studies and 19 cases of field study in Yanbian, China. The results are as followings. In immigrating settled period, floor plans of the rural houses have tended to be continued the pattern of the Korean traditional rural houses. Nevertheless China was changed socialism system, rarely floor plans were influenced by the system during this period. From 1960s to 1970s, the livestock and rural mechanization are influenced by the "People's Commune" policy. The "Barn" and "Mill" were converted into "warehouse". The residential part consists of one Jeongji (space mixed dinning and kitchen) and one to three of Ondolbang (room). From 1980s to 1990s influenced by the policies of "Cultural Revolution", "Birth Control" and "Chinese Economic Reform", the Korean traditional customs like "elders first" and "distinction between the male and female have been gradually vanished. Meanwhile, spaces of the rural houses have consisted of Jeongji, big Utppang (room), and warehouse. Each space is opened and mutual. Since 2000, influenced by the policy of a "new Socialist Countryside Construction", the bathroom and kitchen are added in interior spaces, the life style in rural houses has been changed as for both the sedentary style and western style.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.1
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• pp.159-165
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• 2009

In this study, using a periodical ground structure(PGS) on GaAs monolithic microwave integrated circuit(MMIC), transmission line with a high isolation characteristic was developed for application to compact signal/bias lines of highly integrated MMIC. And the origin of the high isolation characteristic was theoretically investigated. The high isolation characteristic was originated from a resonance between adjacent microstrip lines employing PGS. With only a spacing of $20{\mu}m$, the coupled microstrip line employing PGS showed an isolation value of -47 dB at 60 GHz. The frequency range for high isolation was easily controlled by changing the PGS structure. Above results indicate that microstrip lines employing PGS are very useful for application to compact signal/bias lines of highly integrated MMIC requiring a high isolation characteristics between lines. In addition, equivalent circuit employing closed-form equation for the coupled line with PGS was also extracted.

• The Journal of Korean Physical Therapy
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• v.28 no.2
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• pp.136-141
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• 2016

Purpose: In this study experiments were performed during 6 weeks with 40 adults, 20 subjects in the waist stabilization exercise with blood flow restriction group and 20 subjects in the waist stabilization exercise without blood flow restriction group, in order to determine the impact of waist stabilization exercise on White Area Index (WAI) followed by blood flow restriction. Methods: Thickness of external oblique abdominal muscle, internal oblique abdominal muscle, and transversus abdominis muscle, as well as density and WAI of external oblique abdominal muscle were measured, followed by performance of repeated ANOVA. Results: Significant difference in thickness of external oblique abdominal muscle according to periodical difference was observed between groups (p<0.05). Significant difference in thickness of internal oblique abdominal muscle and transversus abdominis muscle according to periodical difference was observed between groups (p<0.05). Significant difference in density and WAI of external oblique abdominal muscle according to periodical difference was observed between groups (p<0.05). Conclusion: In conclusion, significant difference was observed after waist stabilization exercise with blood flow restriction. These results can be used as basic data for future research on waist stabilization exercise and blood flow restriction exercise.

• Journal of the Korean Society for Library and Information Science
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• v.43 no.1
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• pp.189-214
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• 2009

The study acknowledges the values of periodical indexing as information resources. The study identified periodicals users' needs of article indexing services based on focus group interviews. The study also conducted a comparative study of periodicals indexing services of libraries and databases in Korea and the US. The study argues for the need of seamless services for users of periodical articles indexing services. The study also recommends the elements needed for improving the current service, which includes establishing a collaborative indexing system, adopting a metadata standard, implementing authority files, incorporating social web services, offering diverse ways of information discovery based on facet approach, and stabilizing identification systems.

• 사회경제평론
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• v.29 no.1
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• pp.71-98
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• 2016

This study reveals the followings in the Tugan's business cycle thoery. First, Tugan tried to construct a business cycle theory based on his market theory. But Tugan' theory is lack of logical consistency. Second, Tugan's critics as well as defenders did not understand his theoretical error. Underconsumption theorists did not evaluate Tugan's periodical crisis theory while only criticizing Tugan's crisis theory neglected a consumption. Bauer developed Tugan's periodical crisis by using the reproduction scheme including a hoarded money. Hilferding only constructed a theory of crisis properly criticizing Tugan's crisis theory on the basis of Marx's concept of crisis.

• Journal of the Korea Furniture Society
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• v.23 no.2
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• pp.130-143
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• 2012

The rapid increase in apartments of Korea brought about overall changes in the life style, and definitely played the biggest role to convert into western style. Since 1960, furniture has been changed for 50 years along with apartments, but furniture companies and the academic world had insufficient historical materials and lack of study. In addition, considering the changing trend according to residents' life style, the data of furniture industries should be collected to study every year or in 5 years at least. Therefore, this study aims to provide basic data that gives historical materials or design clues based on recent AV equipment-oriented storage furniture in the living room that prioritized design in public space. Accordingly, the study looked into the periodical trends of Korean furniture industries, analyzed 10 furniture companies in Korea which is actively doing business as the sample and arranged key points of periodical changes of furniture in the table, and suggested the conclusion according to the image map, style, color, material, and function.