• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.5
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• pp.30-44
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• 2002

This study is conducted to analyze the change of location and soil characteristics effect on the condition of urban forest in Urban Park and Green Open Space The results of this study are as fallows; 1. Soil acidity is indicated pH 3.88 in Sasang park, pH 4.38 in Hwaji park, pH 4.40 in Daeyeon park, pH 4.68 in Sanseong amusement park, pH 5.15 in Molundae amusement park. 2. Species diversity indices of indicated Sasang park 0.9932, Hwaji park 1.1975, Daeyeon park 1.2160, Sanseong amusement park 1.3080, Molundae amusement park 1.3233 is due to location and soil environment in addition to air pollution effects. 3. The vitality of Pinus thunbergii 27.5ER in Sasang park, 24.9ER in Hwaji park, 24.5ER in Daeyeon park, 23.6ER in Sanseong amusement park, 21.0ER in Molundae park. This shows that tree vitality are impacted by location and soil characteristics. On the basis of the result above, vegetation devices are suggested : 1) Robinica pseudo-acacia management, 2) removing the hazard plants; Smilax china, Humulus japonicus, Pueraria thungergiana, 3) improving soil hardness and soil acidity.

• The KIPS Transactions:PartC
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• v.9C no.2
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• pp.277-282
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• 2002

In general, requirements for QoS are different according to the type of services in wire-line and wireless ATM networks, and real-time video service is more sensitive to cell transmission delay than to cell loss. Existing handoff schemes emphasizing prevention of cell loss had limitations in cell transmission delay to satisfy QoS. In this paper, a novel scheme to transmit ATM cells with low CLP(when CLP = 0) prior to others and discarding cells with high CLP(when CLF = 1) in ATM cell header among cells to be forwarded to new base station during handoffs in real-time VBR service is proposed. The proposed scheme is proven to be suitable for the satisfaction of QoS of real-time VBR service and appropriate for fast handoffs by giving high CLP value to less meaningful MPEG frames through simulations.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.3
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• pp.229-236
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• 2017

In this study, a direct contact membrane module was manufactured to be used in a pilot scale membrane distillation process to treat $3m^3/day$ of the digestate produced from anaerobic digestion of livestock manure. In order to investigate the performance of the membrane module, permeate flux was measured with and without spacer inside the module under various condition of temperature difference and cross flow velocity (CFV) through the membrane surfaces. Flux recovery rate after chemical cleaning was also investigated by applying three different cleaning methods. Additionally, thermal energy consumption was theoretically simulated based on actual pilot plant operation conditions. As results, we observed flux of the module with spacer was almost similar to the theoretically predicted value because the installation of spacer reduced the channeling effect inside the module. Under the same operating condition, the permeate flux also increased with increasing temperature difference and CFV. As a result of chemical in-line cleaning using NaOCl and citric acid for the fouled membranes, the recovery rate was 83.7% compared to the initial flux when NaOCl was used alone, and 87% recovery rate was observed when only citric acid was used. However, in the case of using only citric acid, the permeate flux was decreased at a rapid rate. It seemed that a cleaning by NaOCl was more effective to recover the flux of membrane contaminated by the organic matter as compared to a cleaning by citric acid. The total heat energy consumption increased with increasing CFV and temperature difference across the membrane. Thus, further studies should be intensively conducted to obtain a high permeate flux while keeping the energy consumption to a minimum for a practical application of membrane distillation process to treat wastewater.

• Journal of Wetlands Research
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• v.12 no.1
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• pp.83-94
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• 2010

Purpose of this study is to define the wise use of Nakdong River estuary based on the expert's survey aiming to identify the core conservation area, the buffering area and the transition area of the estuary. The boundary of the each area is determined by overlaying the expert's opinion of the conservation area, the Biotop conservation value evaluation carried out by Busan Metropolitan city and the designated legal boundary of conservation such as Cultural Reserve area and Wetland Reserve area. Then the concept for wise use of the core preservation area, the buffering area and the transition area is set by the discussion, brainstorming and several workshops. We believe this research leads the sustainable development in the area of the Nakdong River estuary and helps to minimize the conflict among the stakeholders.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.482-486
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• 2008

It has been built or remodeled in every year train maintenance centers including subways. However, there is no standard to measure exact capacity. In today, most of criteria is referenced on Japanese. In general, we can standardize the process for 'Train Overhaul Maintenance' because its processes are similar or same patterns. The processes can be the base standard of train maintenance after being classified in detail and validating it. This study is adapt BPR methodology to present standardizes processes and the processes are mapping to layout drawing to constraint from the real world, and then evaluate the capacity using simulation. To guarantee objectivity of input data, we use research data by the National Railroad Administration and Association of Japanese Railway Engineering. Using these data to simulation, we compare to the 'Allowances' and evaluate its adequacy.

• Journal of the Korea Society of Computer and Information
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• v.15 no.9
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• pp.165-172
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• 2010

Communication problems have been regarded as one of the biggest causes in trouble in many industries. This led to extensive research on communication as a part of human error analysis. The results of existing researches have revealed that maintaining a good quality of communication is essential to secure the safety of a large and complex process system. In this paper, we suggested a method to measure the quality of communication during off-normal situation in main control room of nuclear power plants. It evaluates the cosine similarity that is a measure of sentence similarity between two operators by finding the cosine of the angle between them. To check the applicability of the method to evaluate communication quality, we compared the result of communication quality analysis with the result of operation performance that was performed by operators under simulated environment.

• Korean Journal of Optics and Photonics
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• v.22 no.3
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• pp.151-158
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• 2011

This paper reports design and demonstration of optical systems for reflective-type remote optical displacement sensors. Optical systems for light illumination sources and a position sensitive detector (PSD) for the displacement sensor were developed to sense displacement of bridges and instability of skyscrapers in a distance range from 10 m to 250 m to an accuracy better than a few mm. Performance of the optical systems was verified by composing a displacement sensor and by using it in measurement of displacement of a remote target with proper reflective optics depending on distance. The displacement sensor was composed of two LED light sources, each with collimating optics, and a two-dimensional PSD with telescope-type optics. Its displacement resolutions was measured to be 0.1 mm at a distance of 10 m and less than 3 mm at a distance of 250 m.

• Journal of Internet Computing and Services
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• v.22 no.2
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• pp.51-58
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• 2021

Three degrees of freedom plus(3DoF+) and six degrees of freedom(6DoF) system, which supports a user's movements in graphical and natural scene-based virtual reality, requires multiple high-quality and high-resolution videos to provide immersive media. Previous video quality assessment methods are not appropriate for the 3DoF+ and 6DoF system assessment because different types of artifacts occur in these systems which are not shown in the traditional video compression. This paper provides the performance assessments of several quality assessment methods in 3DoF+ system. Furthermore, this paper presents a super metric, which combines multiple quality assessment methods, thereby it showed a higher correlation coefficient with the subjective quality assessment than the previous methods. Experimental results on 3DoF+ immersive video showed 0.4513 gain on correlation coefficient with subjective quality assessment compared to that of peak signal-to-noise ratio(PSNR).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.515-522
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• 2018

Current signs of a downturn in South Korea's economy include the sharp drop in consumption. Considering internal and external complications such as the raise in minimum wage and fierce global competition, people's taste and purpose of consumption is shifting as well. Under such circumstances, crowdfunding provides a new investment and distribution channel for businesses in their initial stages. Crowdfunding can serve as a key driver of growth in early stages of business operations and lead to growth in consumption as a new distribution channel. This study explores how customers perceive the process of reward crowdfunding, especially when it comes to fairness in procedure, interaction, and distribution. In addition, we further seek how perceived fairness affects customer satisfaction and loyalty in the industry.

• Journal of Sensor Science and Technology
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• v.28 no.3
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• pp.198-204
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• 2019

In this study, we propose a wearable force sensor using 3D printed mold and liquid metal. Liquid metal, such as Galinstan, is one of the promising functional materials in stretchable electronics known for its intrinsic mechanical and electronic properties. The proposed soft force sensor measures the external force by the resistance change caused by the cross-sectional area change. Fused deposition modeling-based 3D printing is a simple and cost-effective fabrication of resilient elastomers using liquid metal. Using a 3D printed microchannel mold, 3D multichannel Galinstan microchannels were fabricated with a serpentine structure for signal stability because it is important to maintain the sensitivity of the sensor even in various mechanical deformations. We performed various electro-mechanical tests for performance characterization and verified the signal stability while stretching and bending. The proposed sensor exhibited good signal stability under 100% longitudinal strain, and the resistance change ranged within 5% of the initial value. We attached the proposed sensor on the finger joint and evaluated the signal change during various finger movements and the application of external forces.