• Journal of the Optical Society of Korea
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• v.19 no.4
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• pp.357-362
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• 2015

We examine the principle of a modified Pound-Drever-Hall (PDH) technique to measure the free spectral range of a Fabry-Perot etalon (FPE). The FPE's periodic transmission of phase-modulated light allows us to adopt a sampling theorem to develop a new relationship for the PDH error signal. This leads us to find the key parameters governing the measurement accuracy: the phase modulation index ${\beta}$ and the FPE finesse. Without any additional complexity for background noise reduction, we achieve a measurement accuracy of 0.5 ppm. The improvement is mainly attributed to the wide-band phase modulation approaching ${\beta}=10$, and partly to the use of both reflected and transmitted light from the FPE and good FPE finesse.

• Journal of environmental and Sanitary engineering
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• v.10 no.1
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• pp.66-75
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• 1995

This survey is executed about the water quality and improvement measure of Imjin- river. The results are summarized as follows; 1 ) Ammonia nitrogen concentration in tap water was two times higher than drinking water standard. 2) The concentration of BOD in textile wastewater was 235ppm which is higher than wastewater distribution standard and leather wastewater showed high nitrogen concentration. 3) Water quality of the Imjin- river upstream was not in problem but that of Shin- stream showed somewhat high concentration in BOD, COD, and ammonia nitrogen. Especially the detected Cynide compound on the lower of Shin- stream implied seriously polluted condition. 4) The heavy metal in soil of the river bed was not detected but iron, zinc was detected to high concentration. 5) It Is urgently suggested to build more municipal sewage and sanitary treatment plants, and run dredging and river bed rearrangement project. 6) The Construction of the wastewater treatment complexes of relevant industries shall be propelled as soon as possible.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.569-570
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• 2009

An improvement of the test method is proposed to more accurately measure early-age autogenous shrinkage in concrete particularly within first 24 hours after casting. Experiments were conducted considering existing and improved method. In improved method, hydration temperature was artificially controlled to prevent thermal deformations. Test results indicate that the autogenous shrinkage calculated by existing approach is underestimated which might be due to the wrong assumption of considering the thermal dilation coefficient to be constant (equal to 10 ${\times}$ $10^{-6}/^{\circ}C$) at early-age. We recommend that the proposed method should be adopted to better assess precise value of autogenous shrinkage or an appropriate method of determining the time-evolution of thermal dilation coefficient be considered.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.8-9
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• 2014

At the moment, construction industry has negative images such as faulty construction, 3D industry and corruption/bribe and they are being projected onto normal people and those engaged in the industry through various news media. Not only does this worsen the lack of skilled manpower by affecting high school students who will be responsible for the construction industry in the future but also makes the future of the industry uncertain by promoting the avoidance of industrial jobs. Therefore, this study suggested basic data for improving the images of construction industry by investigating interest and images of workers in the industry that high school students think as promising construction manpower, and extracting the present negative images through evaluation of associated images.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.469-474
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• 2008

The reason for crashworthy landing gear is to contribute to the overall aircraft design goals in the event of a crash. One of crashworthy landing gear design approaches is inclusion of structural fuse. Structural fuse is used to control the mode of failure of landing gear. If structural fuse doesn't work at desired condition, other unexpected accidents can occur. In this paper, failure probability is calculated for landing gear structural fuse and improvement measure is introduced to improve failure probability of structural fuse.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.10a
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• pp.133-145
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• 2001

This paper presents quality and measure controls of Plastic Board Drains(PBD) for improvement of soft ground. Laboratory and field tests has been carried out to evaluate the quality of PBD focussing on : discharge capacity of flow area; permeability of filter sleeve; migration of fine particles; deformed shape of PBD; consolidation of clay in the close vicinity of PBD; tensile strength of PBD; long-term consolidation behavior of clay-PBD. Test results show that the quality of PBD is sufficient to perform the improvement of soft silty and clayey ground. But, geotechnical engineer must make efforts minimizings of PBD damage and ground disturbance, continuity of drainage system during construction. Adequate monitoring system should apply at ground focussing on number, location, and accuracy of geotechnical instrumentation, measurement and evaluation of data for ground behaviour.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.34 no.4
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• pp.42-48
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• 2011

This paper proposes performance measurement method of quality small-group activity in business. This paper collects and analyzes quality circle activities data respect to tangible and intangible effect in national quality circles competitions festival. This paper proposes QPI (quality-circle performance index) based on Balanced Scorecard for quality small-group activity in quality improvement area. QPI is to measure the performance of quality improvement activities in the business firms. QPI is able to use widely in industries to provide a performance measure of quality small-group activity. In this paper, we propose the application method of QPl.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.27 no.4
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• pp.170-178
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• 2004

As quality becomes a primary leading factor of organizational success, various management strategies have been introduced to improve quality competitiveness. Quality competitiveness, however, is difficult to measure and numerous organizations are struggling to set realistic improvement objectives. The primary purpose of this research is to propose a systematic approach to help the practitioners develop an improvement plan for their organizational quality competitiveness. This approach employs DEA(Data Envelopment Analysis) to evaluate relative efficiency among companies which make efforts to improve their quality competitiveness. It presents an integer programming model to elicit an optimal improvement plan for meeting a target level. A decision support system is also developed for the managers to plan a sequential improvement plan based on both DEA model and the integer programming model.

• Journal of the Korean Mathematical Society
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• v.36 no.1
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• pp.193-207
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• 1999

Let ${\gamma}$ : Ilongrightarrow R2 be a sufficiently smooth curve and $\sigma$${\gamma}$ be the affine arclength measure supported on ${\gamma}$. In this paper, we study the Lp - improving properties of the convolution operators T$\sigma$${\gamma}$ associated with $\sigma$${\gamma}$ for various curves ${\gamma}$. Optimal results are obtained for all finite type plane curves and homogeneous curves (possibly blowing up at the origin). As an attempt to extend this result to infinitely flat curves we give and example of a family of flat curves whose affine arclength measure has same Lp-improvement property. All of these results will be based on uniform estimates of damping oscillatory integrals.

• Journal of the Korean Home Economics Association
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• v.24 no.3
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• pp.143-153
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• 1986

This study is intended to develop a scale to measure familism. Construction of this scale is based on a sample of 448 married males and females living in Seoul. This scale to measure familism is developed by employing a type of item analysis method called correlation analysis. 13 items are selected by correlation analysis, and these are found statistically significant even by analysis based on the criterion of internal consistency. Validity of this scale is evidenced by logical validation, jury opinion and independent criteria. Reliability estimate assessed by Cronbach's alpha coefficients is .759. This scale comprises the following 4 aspects of familism: 1) Support for filial piety and ancestor worship. 2) Integration of individual activities into family ones for achievement of family objectives. 3) Obligation to support individual family members and give them financial assistance when needed, on the assumption that properties such as land, money, etc. belong to family. 4) Mutual aid in psychological and social aspects between parents and married children, and married children and their married siblings. It is concluded that this familism scale represents an improvement on other measure of familism, but that a number of methodological issues remain to be further studied.