• KSBB Journal
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• v.9 no.5
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• pp.469-474
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• 1994

The purpose of the work was to evaluate the feasibility of a biological treatment process for the phenoxy alkanoic herbicide 2,4-D(2,4-dichlorophenoxyacetic acid) as a commercial pesticide. The phenoxy herbicide was 2,4-D amine salts which contained 40%(vol/vol) 2,4-D and 60%(vol/vol) solvent. A microbial consortium has been derived by enrichment with 2,4-D. The consortium utilized 2,4-D as the sole source of carbon and energy. Optimal pH on the 2,4-D degradation was 7.0 in this experiment. As concentrations of 2,4-D were increased, the degradation by microbial consontium became inhibited. The amendment with yeast extract and ascorbic acid accelerated the degradation of 2,4-D. High performance liquid chromatography methodology was used to measure 2,4-D and it also resolved 2,4-DCP(2,4-dichlorophenol), the corresponding phenol as intermediate. Gas chromatography-mass spectrometry was used for preliminary identification of the intermediate 2,4-DCP. UV scans of spent cultures showed that the maximum absorption of 2,4-D at the wavelength of 283 nm was decreased toward the end of incubation, but the consortium displayed no detectable spectral changes or peak shifts in the UV absorbance.

• Korean Journal of Optics and Photonics
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• v.29 no.3
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• pp.99-103
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• 2018

Optical coherence elastography (OCE) is based on optical coherence tomography (OCT), which is a noninvasive, high-resolution, cross-sectional imaging technique. In this paper, we have developed dynamic optical coherence elastography to measure elasticity, a mechanical property of tissue, by phase difference. A piezoelectric actuator was used for sinusoidal mechanical loading of samples. Before applying this method to biomaterial, we assessed the feasibility of OCE with samples of sponge, eraser, and sharp lead. Cross-sectional and phase-difference images of the sample were obtained under sinusoidal loading. The strain rate was calculated from the phase-difference information. To obtain the envelope of the phase-difference oscillations along the horizontal direction, Hilbert transformation was performed at each depth. The elevation of the envelope was represented by color mapping, and we could measure the relative elasticity within the sample by comparing the elevations. Finally, there was an advantage when we calculated the shear rate using self-interference in the sample arm, instead of the interference between sample and reference arms.

• Ocean and Polar Research
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• v.27 no.4
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• pp.451-461
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• 2005

The $CO_2$ storage in geologic and oceanic reservoirs is considered to be one of the carbon management strategies for responding to global climate change. Ocean carbon sequestration is purposeful storage acceleration into the ocean of large amounts of carbon that would accumulate in the atmosphere and naturally enter the ocean over a longer timespan. Some technologies for $CO_2$ ocean sequestrations have been developed as a nation project. However, $CO_2$ ocean sequestrations are attractive because they have the advantage of vast capacity sequestration far away from industrial areas, and offer easier monitoring whereas less economic advantage has been indicated as one of the key barriers compared with $CO_2$ geosphere sequestration, which is produced as a byproduct. In this paper, a conceptual design for $CO_2$ ocean sequestration is introduced, and the preliminary examination is described. As a result, the $CO_2$ price, US$ 24/t shows far away from the economics. The causes come from the expensive $CO_2$ recovery cost and the low $CO_2$ price. The expensive $CO_2$ recovery cost is because too much electricity and water are consumed. In order to look for an economic balance point for $CO_2$ ocean sequestration, NPV=0, it is increases the $CO_2$ price. Finally 60.4$ per ton is found to be the balance price.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.6
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• pp.661-665
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• 2001

This paper deals with optimal mooring system to secure fish cage in a desired location, Through field investigation and paper works, we surveyed disasters by breakdown of cage frame and mooring system due to higher wave attack and selected compliant buoy mooring method for shallow water mooring system against severe coastal external forces. To analyze interaction between external forces and compliant buoy mooring system, theoretical model has developed as quasi-static nonlinear analysis. After verifying the feasibility of the numerical model compared with experiment, static analysis has tried for various mooring systems with different angle of array, number of mooring points, length of horizontal and inclined rope. Optimal mooring method using compliant buoy has selected for fish cage through numerical simulation. This results can apply for preliminary design for cage mooring system.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.3
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• pp.179-190
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• 2020

As the business environment is rapidly changing with globalization and complexity of information flows, the uncertainty is also very increased for project environment. Although many studies have been conducted to find out the critical factors for project success, there still exist different views to define project success. Furthermore, implementing success formula for one project does not necessarily guarantee a success for another project since there are other elements that impede the success of project. In this regards, it is imperative to examine what are the barriers to project success. This study aims to examine the barriers that impede the success of project. Past literature was thoroughly reviewed to collect and develop a preliminary list of elements that affected project performance negatively. Experts were interviewed to refine the list and the final list of the measurement items were developed. A survey questionnaire was developed with the final list of measurement items, and a survey was conducted on the practitioners with project experience. After the survey, an exploratory factor analysis was conducted on the final list to extract the component dimensions which in turn formed the group of project barriers. The exploratory factor analysis provided ten factors, which are difficulty of process management, failure of project feasibility analysis, cost overruns and lack of cost benefits, unclarity project plan, strategic consistency error, stakeholder conflict, inaccuracy of requirement definition, disturbance of communication, technical environment change, negative attitude of top management.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.12
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• pp.3055-3062
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• 2014

3D integral imaging technique with an active mask is capable of displaying real 3D images with high resolution in space. In this paper, we present a novel 3D/2D convertible integral imaging display system using an active mask. For the proposed method, the principles of 3D, 2D, and 3D/2D composed operations are explained according to the displayed images through two LCD panels. In 3D mode, the elemental images and the mask images are displayed in two display panels. On the other hand, the light source image and 2D image are displayed in 2D mode. In addition, 3D/2D mode is obtained using the spatial separation for 3D and 2D modes. To show the feasibility of the proposed method, we carry out the preliminary experiments and present the optical results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9B
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• pp.1287-1294
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• 2010

The traffic classification is a preliminary and essential step for stable network service provision and efficient network resource management. While a number of classification methods have been introduced in literature, the payload signature-based classification method shows the highest performance in terms of accuracy, completeness, and practicality. However, the payload signature-based method has a significant drawback in high-speed network environment that the processing speed is much slower than other classification method such as header-based and statistical methods. In this paper, We describes various design options to improve the processing speed of traffic classification in design of a payload signature based classification system and describes our selections on the development of our traffic classification system. Also the feasibility of our selection was proved through experimental evaluation on our campus traffic trace.

• Resources Recycling
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• v.24 no.2
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• pp.29-35
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• 2015

A feasibility test was carried out for upcycling of waste jelly-filled communication cables together with the development of environmentally friendly processes and equipments. High pressure water injection is proved to be an exceptionally environmentally friendly and highly efficient mechanical process. A batch-type cable barking equipment is designed and built on the basis of computational fluid dynamics modelling. It is optimized in terms of energy consumption and productivity with very high copper recovery of 99.5%. Copper nano-powder is prepared by an electrical wire explosion in ethanol media in order to improve the value of final products, and the preliminary economical assessment is also conducted.

• Journal of KIBIM
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• v.8 no.3
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• pp.31-42
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• 2018

This study focuses on the BIM request for information(RFI) processing performance and quantitatively analyzes the performance of the BIM coordinator and the loss due to the waiting of the project participants. For these purposes, a method to quantitatively evaluate the performance of the BIM coordinator was proposed using a queueing model. For the verification, two projects in which BIM was applied in the construction phase were selected, and the BIM RFI data were collected through the analysis of the BIM monthly report and BIM coordinator work log of each project. In addition, the BIM input personnel, labor cost, and productivity data were collected through interviews with the experts of the case projects. The analysis of the BIM RFI processing performance of the BIM coordinator using the queueing model exhibited on a probabilistic basis that the waiting status of the project participants could vary depending on the preliminary BIM application to the design verification as well as the input number and level of the BIM coordinator personnel. In addition, the loss cost due to the waiting of the project participants was analyzed using the number of BIM RFIs waiting to be processed in the queueing system. Finally, the economic feasibility analysis for the optimal BIM coordinator input was performed considering the loss cost. The results of this study can be used to make decisions about the optimal BIM coordinator input and can provide grounds for the BIM return on investment (ROI) analysis considering the waiting cost of the project participants.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.3
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• pp.18-24
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• 2017

Appropriate selection of the starter is essential for successful starting of the gas-turbine engine. Thus, aerodynamic drag during starting phase should be analyzed to assess the feasibility of the starter. In this paper, aerodynamic drag is modeled based on the speed profile from the engine coast down test, and it is scaled with respect to the target engine by comparing the compressor load. Afterward, the govern equation of the starting phase is developed with the torque model of the starter, and the design scheme to select the feasible starter will be finally suggested. The proposed model of starting phase will be useful to perform a preliminary design of the starting system of the gas-turbine engine.