• KIPS Transactions on Computer and Communication Systems
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• v.12 no.9
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• pp.263-272
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• 2023

Industrial Internet of Things (IIoT) is an important factor in increasing production efficiency in industrial sectors, along with data collection, exchange and analysis through large-scale connectivity. However, as traffic increases explosively due to the recent spread of IIoT, an allocation method that can efficiently process traffic is required. In this thesis, I propose a two-stage task offloading decision method to increase successful task throughput in an IIoT environment. In addition, I consider a hybrid offloading system that can offload compute-intensive tasks to a mobile edge computing server via a cellular link or to a nearby IIoT device via a Device to Device (D2D) link. The first stage is to design an incentive mechanism to prevent devices participating in task offloading from acting selfishly and giving difficulties in improving task throughput. Among the mechanism design, McAfee's mechanism is used to control the selfish behavior of the devices that process the task and to increase the overall system throughput. After that, in stage 2, I propose a multi-armed bandit (MAB)-based task offloading decision method in a non-stationary environment by considering the irregular movement of the IIoT device. Experimental results show that the proposed method can obtain better performance in terms of overall system throughput, communication failure rate and regret compared to other existing methods.

• Transactions of the Korean hydrogen and new energy society
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• v.12 no.4
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• pp.277-285
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• 2001

We developed a compact, 10 kWe, purifier-integrated reformer which supplies hydrogen for fuel cell vehicles. Our proprietary technologies regarding hydrogen purification by palladium alloy membrane and catalytic combustion by noble metal coated wire-mesh catalyst were combined with the conventional methanol steam reforming technology, resulting in higher conversion, excellent quality of product hydrogen, and better thermal efficiency than any other systems. In this system, steam reforming, hydrogen purification, and catalytic combustion take place all in a single reactor so that the whole system is compact and easy to operate. The module produces $8.2Nm^3/hr$ of 99.999% or higher purity hydrogen with CO impurity less than 10 ppm, which is equivalent to 10 kWe when PEMFC has 45 % efficiency. Thermal efficiency of the module is 81 % and the power density of the module is 1.6 L/kWe. As the results of experiments, cold-start time has been measured about 20 minutes. Response time of hydrogen production to the change of the feed rate has been within 1 minutes.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.174-174
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• 2012

최근 농업용저수지의 경우 기상이변에 따른 수위조절을 위하여 다량의 수문을 일시에 개방하는 사례가 지역적으로 증가하고 있는 추세이다. 그에 따라 당초 목적인 농업용수를 위한 취수시설이 최근 홍수조절용으로 활용됨에 따른 취수시설 내 공동현상이 발생하고 있다. 이러한 공동현상으로 인해 수시설물의 안정성에 문제가 발생하고 그에 따른 2차 재해위험이 있을 수 있다. 따라서 본 연구에서는 공동현상 방지를 위해 취수시설 공기관 설계기준에 대하여 고찰하였다. 공동현상을 방지하고 홍수량을 적절하게 배제하기 위해서 유입되는 공기량산정식이 필요하다. 공기관 단면결정은 농업생산기반정비사업 설계기준(필댐)의 구조설계 부분에 정리되어 있지만 이는 이수측면에서 설계 및 시공이 진행됨에 따라서 취수에 대한 목적을 달성하기에는 어려움이 있다. 따라서 취수시설의 기능과 역할을 증대시키고자 취수시설 적정 공기관 설계를 분석하여 향후 신규, 개보수 및 현장 유지관리에 활용하기 위한 기초자료를 제시하였다. 이러한 공동현상 및 공기관 설계를 위하여 현장조사, 수치해석, 수리모형시험을 병행하여 문석하였다. 그 결과 취수탑의 형상변수와 수위에 대한 수치해석을 수행하여 변수가 소요공기량에 미치는 영향은 조절게이트 개폐율을 증가시킬수록 소요공기량이 증가하며, 약 80%의 개폐율에서 소요공기량이 최대가 되었다. 방수로 직경이 증가하면, 공기관 입구와 끝단의 압력차가 감소하여 소요공기량이 감소하고, 수위가 증가하면 소요공기량이 증가하는 것으로 분석되었다. 따라서 공동현상 방지를 위해 공기량 산정식은 취수터널에 연직수문이 설치되어 있는 6가지 흐름의 형태에 따라서 $/Q_w=0.04(F-1)^{0.85}$, $Q_a/Q_w=K(F-1)$, $Q_a/Q_w=0.014(F-1)^{1.4}$, $Q_a/Q_w=0.015(F-1)^{1.4}$의 관계식 중 적정한 것을 사용하여야 할 것으로 판단되며, 또한 공기관에 유입부의 허용부압은 수두로부터 1.0m이하로 하고, 공기관 내 풍속은 $45^m/s$를 기준으로 최대 $90^m/s$로 하여야 할 것으로 판단된다.

• Journal of the Korean Applied Science and Technology
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• v.37 no.5
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• pp.1106-1115
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• 2020

Research was conducted on the production of bio-methane for city gas, from food waste digestion gas using two membrane-separation methods(4SBR and 3SDR) in a commercial plant. A purity of 98.9% can be obtained using either method. The recovery rate of methane from the digestion gas was 88.1% for 4SBR and 79.4% for 3SDR. the ratios of bio-methane production to treated digestion gas were 53.5% for 4SBR and 49.4% for 3SDR. However, the 4SBR method had a higher ratio of returned gas(56.5%), approximately twice that of 3SDR, making 3SDR the more desirable method in terms of maximum treat capacity. Therefore, 4SBR seems more economical when the digestion gas to be treated is less than 200 N㎥/day, while 3SDR is more suited to treat gas volumes of more than 240 N㎥/day. The relative deviation of each operation index, compared to mean values, was generally greater for the 4SBR method. Additionally, the correlation coefficients between major system indexes, such as bio-methane production and bio-methane draw out pressure(which is the main control measure of membrane facility) showed that these indexes are more closely related in the 3SDR method.

• Management & Information Systems Review
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• v.37 no.2
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• pp.259-281
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• 2018

Advocates of mandatory IFRS adoption claim that IFRS increase financial statement comparability, which in turn leads to greater cross-border investment(Securities and Exchange Commision, 2008). The notion is that improved financial statement comparability reduces the information acquisition costs of global investors and thereby increase their investment in foreign firms. The purpose of this study is to examine this assertion by examining whether the K-IFRS adoption rusults in improved comparability that leads to increased investment by foreign investment. We also examined whether the relation between comparability and foreign investment has strengthen after adoption of K-IFRS. To achieve the purpose of our study, we measure Korean firms comparability using stock price model, stock return model and cash flow from operation model by Barth et al.(2012). We use both foreign ownership in the end of year and average during the year for dependent variables were to reduce bias. We test our hypothesis using 1,817 firm-year observation of KOSPI firms during the period of our analysis, 2011-2015. Consistent with our hypothesis, we find K-IFRS adoption results in a greater increase in foreign investment in firms with high comparability firms. This result indicate that the adoption of K-IFRS intends to achieve the international accounting convergence as stated in the roadmap and to reduce the Korea Discount.

• Journal of Plant Biotechnology
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• v.41 no.4
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• pp.216-222
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• 2014

This study was carried out to develop an efficient transformation protocol via particle bombardment with PLBs (protocorm-like bodies) in Phalaenopsis. To achieve this aim, osmoticum treatment and an increasing shooting chances in particle bombardment process were applied for this study. In addition, pCAMBIA3301: ORE7 vector which contains a herbicide-resistance bar gene as a selectable marker and ORE7 gene as a gene of interests were employed. With regard to the increasing chances of shooting in particle bombardment, double shooting was the best results with 1.5 ~ 2.5 times higher than those of a single or triple shooting treatment in the productioon of PPT (D-L-phosphinothricin)-resistant PLBs. However, regeneration rate of shoots in double shooting was not high as a single shooting. Further, double shooting showed 35 ~ 40% higher than that of a single shooting in the frequency of browning. Regarding effects of different osmotic treatments, combination of 0.2 M sorbitol with 0.2 M mannitol showed the best results in transformation efficiency, regeneration of transformants and reduction of browning. Putative transgenic Phalaenopsis plants were analyzed by PCR analysis and confirmed the presence of bar and ORE 7 gene. Also, real-time PCR was conducted by using 21 transgenic plants and showed only 4 plants had one copy of transgene; whereas, the other 17 plants had more than 2 copies of transgene. Transgenic phalaenopsis plants produced in this study were transferred to pots and flowered normally without morphological variations in flower and leaf.

• Journal of the Korea Convergence Society
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• v.13 no.3
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• pp.1-9
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• 2022

UML class diagrams are used to visualize the static aspects of a software system and are involved from analysis and design to documentation and testing. Software modeling using class diagrams is essential for software development, but it may be not an easy activity for inexperienced modelers. The modeling productivity could be improved with a dataset of class diagrams which are classified by domain categories. To this end, this paper provides a classification method for a dataset of class diagram images. First, real class diagrams are selected from collected images. Then, class names are extracted from the real class diagram images and the class diagram images are classified according to domain categories. The proposed classification model has achieved 100.00%, 95.59%, 97.74%, and 97.77% in precision, recall, F1-score, and accuracy, respectively. The accuracy scores for the domain categorization are distributed between 81.1% and 95.2%. Although the number of class diagram images in the experiment is not large enough, the experimental results indicate that it is worth considering the proposed approach to class diagram image classification.

• The Journal of Engineering Research
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• v.3 no.1
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• pp.199-205
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• 1998

Cullet Quality Control in auto glass bottle factory is the most important in recent days because of the increasing cost of materials in glass bottle. Since the composition of plate glass cullet is similar, the cullet quality using plate cullet in glass bottle factory is easily controlled. In addition to this, the price of plate glass cullet is so low that the cost reduction can be achieved. If the ratio of plate glass cullet and gush is over 25%, the liquidity of glass water become worse, which is caused by different compositions and viscosity of the components. As a results, Furnace bottom temperature becomes low and glass water becomes inhomogeneous. Thus production efficiency of glass bottle becomes low because of increasing devitrification in Dead Corner part in glass melting furnace. Three experimental methods – (1) increasing melting temperature, (2) using Booster, (3) using bubbler – were performed to increase the furnace bottom temperature and glass water homogeneity. The amounts of plate glass cullet was able to increase up to 90%, 70% and 60% without any devitrification using booster, bubbler and the method of glass melting temperature increase from $1480^{\circ}C$ to $1560^{\circ}C$ respectively. It is not possible to increase the glass melting temperature without the reduction of furnace operation time and the increase of fuel cost. The booster process has disadvantage of much electric energy consumption. Since the bubbler process uses physical convection of melting glass based on compression air, the homogeneity of molten glass is not so good as that of booster process but it can reduce the cost of glass bottle.

• Quality Improvement in Health Care
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• v.15 no.1
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• pp.73-78
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• 2009

문제: 오늘날 간호사는 과거와 달리 현대적 보건의료 요구를 해결할 수 있는 체계적인 이론과 기술을 습득하도록 훈련된 고급 전문 인력이고, 간호행위를 생산하기 위해서는 서비스의 생산원가 뿐만 아니라 전문 인력으로서의 훈련 및 유지비용 등도 투입되어야만 가능하게 함으로서 2008년 7월부터 시행한 중환자실 간호등급에 따른 간호수가 책정으로 인해 중환자실 내에서 이루어지고 있는 많은 간호행위 중 수가를 받을 수 있는 부분이 생기게 되었고 간호행위의 중요성과 더불어 간호를 시행 후 받을 수 있는 수가에 대한 간호사들의 입력에 대한 의무도 늘어나게 되었다. 이에 빈번히 누락되고 있는 간호수가 관리를 통한 경제적 손실을 방지해야 할 필요성을 느껴 개선활동을 하고자 한다. 목적: 2008년 7월부터 시행한 중환자실 간호등급에 따른 간호수가 책정으로 인해 중환자실내에서 이루어지고 있는 간호 행위의 중요성을 인식하고 구체적인 문제 분석과 간호 현장에서의 개선안을 도출함으로써 경제적 손실을 방지할 수 있는 간호수가 누락률을 감소시키고자 함이다. 의료기관: 대구파티마병원 내과 중환자실. 질 향상 활동: 업무개선의 방법으로 환자 개인별 간호수가 입력 누락 방지 체크 리스트 사용 및 처방 전달 시스템의 간호수가 재입력 화면을 이용하여 입력의 용이성 도모하였고 입력된 간호수가를 처방 전달 시스템 간호수가 조회 프로그램을 이용해 익일 누락여부를 매일 모니터링 하였다. 교육 및 홍보활동으로는 간호수가 입력누락 방지를 위한 간호수가 입력 지침을 제작하여 전체간호사는 년 2회, 신규간호사는 개별 교육을 실시하였으며, 월별 간호수가 누락통계를 실명 공고 하여 간호수가 다 빈도 누락 간호사는 추가 개별교육을 실시하였다. 개선효과: 간호수가 입력 프로세스 개선을 통해 간호수가 평균 누락률이 개선 전 6.5%, 개선 후 1.2%로 5.3%의 누락 감소율을 보였으며 역치 5%를 달성하였고 간호수가 누락금액은 개선 전 2,992,752원, 개선 후 590,787원으로 2,401,965원의 누락 효과 비용을 구할 수 있었다. 본 QA활동으로 중환자실 간호수가 전산입력에 대한 체계적인 교육부재와 신규간호사들의 잦은 전산누락이 있어왔으나 표준화 된 체크리스트 지침과 입력확인 작업으로 전산입력 누락률이 감소하는 효과를 가져왔다. 추후 심평원 청구 작업을 하는 부서와 연계되어 실제 청구 누락률에 대한 비교와 간호사 근무연수와 간호수가 입력 누락률에 대한 상관관계 조사를 제언 해 본다.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.12
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• pp.696-704
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• 2015

This study was carried out to evaluate the optimum operational condition of Semi-continuously Fed and Mixed Reactor (SCFMR) to treat the dairy cow manure and saw dust mixture. Step-wise increase in organic loading rates (OLRs) or decrease in hydraulic retention times (HRTs) were utilized until the biogas volume became significantly decreased at mesophilic temperature ($35^{\circ}C$). The optimum operating condition of the SCFMR fed with TS 13% dairy cow manure and saw dust mixture was found to be an HRTs of 25 days and its corresponding OLRs of $4.45kg\;VS/m^3-day$. At this condition the biogas and methane production rates were 1.44 v/v-d and 1.12 v/v-d (volume of biogas per volume of reactor per day), respectively and the TVS removal efficiency of 37% was achieved. The successful operation with such a high OLR was due to the high reactor alkalinity concentration of 14,500~15,600 mg/L as $CaCO_3$ as a result of the characteristic of the original substrate, dairy cow manure and saw dust mixture whose alkalinity was more than 8,000 mg/L as $CaCO_3$. The parameters for the reactor stability, the ratios of volatile acids and alkalinity concentrations (V/A) and the ratio of propionic acid and acetic acid concentrations (P/A) appeared to be 0.11 and 0.43, respectively, that were greatly stable in operation. Free ammonia toxicity was not experienced due to the long term acclimation by the reactor TS content ranged 7.2~10.4% during the entire operational period.