• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.4
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• pp.41-50
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• 1987

The present study was conducted to measure and predict the leachate generation and to establish the methods of leachate control and handling by both field and lab-lysimeter studies. The change of biodegradable matter, field capacity, dry density, quantity and quality of leachate as a function of time of landilling were measured. The model based on the theory of unsaturated flow and contaminant transport in porous media was developed and simulation model was used for the prediction of movement of landfill moisture and for the strength in leachate in terms of organic and inorganic contaminant. The model constructed from the present study in terms of unsaturated decomposition and transport combined with the evapotranspiration and surface runoff showed good agreement with the results obtained by lysimeter studies.

• Journal of Digital Contents Society
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• v.18 no.2
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• pp.403-410
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• 2017

In this paper, the fire extinguisher maintenance system using smart NFC communication and the real-time pressure measurement is proposed. The proposed system consists of three steps in the flow of information. The first step is to identify the fire extinguisher through NFC tagging in the fire extinguisher module using the smart device. The fire extinguisher appearance check and the real-time pressure measurement is performed in the second step, and the last step sends the check status information to the management server. In particular, the actual pressure value is calculated based on the angle of the green area and the indicating needle. Some experiments are conducted so as to verify the proposed system, and as a result, the proposed system shows that the administrator can effectively control the status information of fire safety check.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.11 no.1
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• pp.269-283
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• 1998

Paranasal sinusitis, especially chronic is one of the most common diseases in the field of otolaryngology. It is similar to Bee Yeun(鼻淵) in oriental medicine. Most cases of sinusitis are due to anatomical abnormalities within ostiomeatal unit or disturbed mucocilliary flow. The ostiomeatal unit is the first place of contact with bacteria and allergens during aspiration, and it can be obstructed easily by minute mucosal swelling due to anatomical narrowness. Therefore the treatment of paranasal sinusitis is not easy and often leads to recurrences in spite of long term treatment or surgical therapy. We studied 83 patients who had visited our hospital with complaints of nasal symptoms; they had been diagnosed as having paranasal sinusitis through an endoscopy or CT scan in another hospital and were diagnosed as the paranasal sinusitis through a PNS series. The results were as follows: 1. Age and sex distribution: The most common occurence was found between 6-10 and 1-5 years old. The Males Were 52($62.7\%$) and Females were 31($37.3\%$). 2. By residence 58 cases lived in apts: 25 lived in houses. 3. The longest duration of disease varied from a lower of 13 to a higher of 36 months in 22 cases and from 7 to 12 months in 21 cases. 4. The most common complication & past history with otolaryngologic or allergic disease were adenoid or tonsil hypertrophy & tonsillectomy and adenoidectomy (21 cases). In decreasing order the others were atopic dematitis, otitis media with effusion and allergic rhinitis. 5. Distribution of paranasal sinus disease was most common in both maxillary sinuses in 52 cases. 12 cases showed a normal PNS X-ray series but these had been diagnosed as paranasal sinusitis with an endoscopy or CT scan in another hospital. 6. Common sinusitis - related symptoms were from highest incidence to lowest nasal obstruction, postnasal drip rhinorrhea, frontal headache, cough with sputum. 7. The most administered of prescription was Gamibangpoongtongsungsan and Sunbangpaedoksan extract. 8. In 26 cases the subjects showed significant improvement symptoms in PNS X-ray series : In 21 case showed partial improvement symptoms.

• Journal of the Korea Safety Management & Science
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• v.19 no.2
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• pp.173-180
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• 2017

Omni-channel strategy is an innovative paradigm for integrated information distribution of inventory, sales, operations, marketing, delivery, pickups and returns in supply chain management. Recently the distribution strategy faces new challenges with the advent of mobile distribution channels. Social media with countless apps imposes additional stress on supply chain operations. Due to these changes, distribution network in supply chain is changing naturally and rapidly from multi-channel to omnni-channel platform. Recently numerous domestic distributors establish and adapt this new supply chain optimization tool as a part of seamless flow of movements of goods from one channel to other channels. The objective of this paper is to present a preliminary findings on how omnni-channel affects the supply chain management. A survey is used to ascertain in the degree of omnni-channel implementation and statistical evidence is provided to test sets of hypothesis. The results of the questionnaire showed that consumers' purchasing styles differed by gender, age, purchase purpose, and product type. In particular, women consider purchasing experience in omni-channel to be important. As food and household goods can be conveniently shipped, consumers prefer online purchasing it. Conversely, consumers tend to favor omni-channel strategy in connection with offline experience in IT products.

• KSBB Journal
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• v.15 no.5
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• pp.469-473
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• 2000

We studied the removal of toluene vapors in a lab-scale biofiter. Biofiltration was performed in a column fed in a downflow manner with contaminated air at ambient conditions. The column was packed with a mixture of peat and calstone(5:3 vol. Ratio), which was inoculated with microbes of selected stains(Pseudomonas putida type A). The microorganisms were immobilized on the filter media and biofilms were formed. The fiofilter was operated at various inlet toluene concentrations for days, and treated up to a maximum elimination capacity of $20 g/m^3hr$ at an inlet load of $30 g/m^3hr$, which corresponds to removal efficiencies in the range 20∼90% and a gas retention time of 1 to 2 min. The pressure drop was almost negligible over the biofilter columns, amounting to only $1.062 cmH_2O/m$ and appreciably smaller than other studies. The effects of operating conditions such as flow rate, inlet toluene concentration and moisture content on the performance of the biofilter were sequentially investigated.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.113-116
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• 2005

In general, multiple mobile hosts (MH) access at a base station (BS) that terminates the wired link and relays data flow to the wireless link in wired and wireless heterogeneous network. In this network, the BS is tend to be a bottleneck and to degrade a network performance. Many studies have been done throughout several protocol layers. Especially on the transport layer, many techniques were studied to enhance TCP performance. But most of them are concerned to enhance TCP throughput and TCP fairness is hardly considered. In this paper, an algorithm for enhancing TCP fairness is proposed and its performance is verified by ns-2 simulation.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.14 no.1
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• pp.19-33
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• 2002

A numerical method to efficiently secure necessary design informations of the hydraulic characteristics of rubble mound breakwater was attempted here. The method combines the exterior wave field with the interior wave field which is formulated incorporating porous media flow inside the breakwaters. An approximate method based on the long wave assumption was used for the exterior wave field while a boundary element method was used for the interior wave field. A hydraulic experiment was also performed to verify the validity of the numerical analysis. The numerical results were compared with experimental data and results from existing formulae. They generally agreed in both reflection and transmission coefficients. The calculated pore pressures also showed a similar pattern with experimental data, even if they gave some significant differences in their values fur some cases. The main cause of such differences can be attributed to the strongly nonlinear wave field occurring on the frontal slope of the breakwater. The direct input of dynamic pressures(measured from hydraulic experiment) into the numerical method was suggested as a promising method to enhance the predictability of pore pressures.

• Journal of Life Science
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• v.7 no.2
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• pp.112-118
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• 1997

In previous paper Pseudomonas sp. Ks-96 isolated from the bioconversion into pyrogallol from gallic acid . Continuous bioconversion of pyrogallol was carried out using rotatory disc contactor immobilized Pseudomonas sp. Ks-96 . Enzyme activity of gallate decarboxylase released from Pseudomonas sp. Ks-96 were shown at the highest activity on 24h incubation. Culture media containing gallic acid supplied on the flow rate of 20m${\ell}$/h until thickness of cells wall reached steady state. Bioconversion rate of pyrogallol from gallic acid showed at highest level ranging from 18hr to 36h according to time courses. Continuous bioconversion of pyrogallol using rotating disc contactor was about 82% and 80% between 6 and 8 days at the feeding rate of 300m${\ell}$ per hour in the medium containing 15g/${\ell}$ gallic acid.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.285-285
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• 2017

최근 전 세계적으로 심각해지는 물 부족 현상과 수질오염으로 대량의 원수를 빠른 시간 내에 여과하기 위한 여과장치의 개발 및 효율성 향상을 위한 연구의 필요성이 증가되고 있다. 특히 여과필터의 내부구조에 의해 유동이 편중되는 현상이 발생하면 여과효율 및 여과필터 유지관리에 문제가 발생되기 때문에 최적의 여과필터를 설계하는 것이 중요하다. 이에 본 연구에서는 수리모형실험으로 검토하기에 어려움이 있는 여과기 내부구조에 대한 유동특성을 수치해석을 이용하여 검토하였다. 수치해석은 유한요소법 기반의 수치모형으로 여과기 내부를 상세하게 모의할 수 없기 때문에 유한체적법 기반인 ANSYS CFX 모형을 이용하였다. 여과기 내 여과필터는 두께 2.0 mm, 공극율 25%로 가정하고 다공성 기법(porous media)을 적용하였다. 검토를 위한 경계조건은 유입부에 목표 취수량, 유출부에 대기압 조건을 적용하였으며, 여과기에 비해 매우 작게 구성된 여과필터 내부의 유동특성을 검토하기 위해 여과기는 최소 3.0 mm, 여과필터는 1.0 mm의 격자를 적용하였다. 현재 실제 여과시설에 적용되고 있는 여과기 제품 형상을 기준으로 여과기 내부 흐름공간의 크기 및 각도 조정에 따른 유동특성을 검토하여 여과효율을 비교하였으며 통과유량, 유속, 유속벡터 등을 검토하여 균등한 유량과 유속이 발생되는 최적의 여과장치 구조를 도출하였다. 본 연구에서 여과기 내부 구조 변경에 따른 유동특성 검토를 통해 도출된 최적의 여과기 내부크기 및 각도에 대한 설계인자는 여과기 내 여과필터의 효율을 증가시킬 뿐만 아니라 내구성 증진에 도움이 될 것으로 예상된다.

• Journal of Soil and Groundwater Environment
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• v.26 no.6
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• pp.1-17
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• 2021

Self-potential (SP) surveys measure naturally occurring differences in electrical potential in the absence of artificial sources and have been applied to various fields since the first application in mineral explorations. Among various causes of SP occurrences, streaming potential is generated by the flow of groundwater, and makes SP surveys suitable for the exploration of groundwater table fluctuation, fractures, sinkholes and landslide occurrences. Recently, there has been many studies that applied SP surveys to monitor water leakage through dikes and embankments. In this review paper, we first review the characteristics and theoretical backgrounds of streaming potential in saturated or unsaturated porous media to introduce it in the embankment among various application field. After the review of the background theory, we review the past cases of field SP surveys on dikes and embankments and also the characteristics of field streaming potential data in the surveys. Further, by analyzing past studies of qualitative as well as quantitative interpretation of SP survey data, we show the possibility of quantitative interpretation of streaming potential data obtained on dikes and embankments. Consequently, it is hope that this review paper helps researches on SP surveys on dikes and embankments, and provides basis for interpretation methods of the SP data to identify leaked area and further leakage rate (or permeability).