• 한국정보통신학회논문지
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• 제20권10호
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• pp.1903-1911
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• 2016

오늘날 MANET에 대한 관심의 증대와 더불어 효율적인 MANET 라우팅프로토콜에 대한 연구가 활발히 진행중에 있다. 본 논문은 전술적 MANET 환경에서 Topology의 빈번한 변화와 제한적 무선환경에 적응된 라우팅 프로토콜을 개선하기 위해, 기존의 AODV라우팅 경로설정과정에서 Hop-Count만을 참조하던 방식에서 각 구간의 채널용량을 참조하는 LQA-AODV를 제안하였다. 제안된 LQA-AODV는 기존의 AODV라우팅프로토콜의 경로탐색과정에서 발생하는 RREQ메시지 포맷에 채널용량에 대한 Cost값을 추가하고 경로설정 시 구간별 누적 Cost값을 비교하여 경로를 설정하도록 하였다. 성능검증을 위해 NS2.35를 사용하였으며, 전술무선환경이 반영하기 위해 Link-Qualty모델을 적용하였다. 시뮬레이션은 LQA-AODV와 기존의 AODV를 비교분석하였으며, 그 결과 Packet Delivery Ratio와 End-to-End Delay 측면에서 성능이 일부 개선된 것을 확인할 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제33권11호
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• pp.1531-1541
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• 2023

Lipase is a well-known and highly in-demand enzyme. During the last decade, several lipase optimization studies have been reported. However, production costs have always been a bottleneck for commercial-scale microbial enzyme production. This research aimed to optimize the conditions for lipase production by Limtongozyma siamensis DMKU-WBL1-3 via a One-Factor-At-a-Time (OFAT) approach combined with statistical methods while using a low-cost substrate. Results suggest that low-cost substrates can be substituted for all media components. An optimal medium was found, using response surface methodology (RSM) and central composite design (CCD), to consist of 0.50% (w/v) sweet whey, 0.40% (w/v) yeast extract (food grade), and 2.50% (v/v) palm oil with the medium pH adjusted to 4 under shaking flask cultivation. From an economic point of view, this work was successful in reducing production costs while increasing lipase productivity. The medium costs were reduced by 87.5% of the original cost while lipase activity was increased by nearly 6-fold. Moreover, lipase production was further studied in a 2-L stirred-tank fermentor. Its activity was 1,055.6 ± 0.0 U/ml when aeration and agitation rates were adjusted to 1 vvm and 170 rpm, respectively. Interestingly, under this optimal lipase production, the yeast showed accumulated lipids inside the cells. The primary fatty acid is a monounsaturated fatty acid (MUFA) that is typically linked to health benefits. This study hence reveals promising lipase production and lipid accumulation by L. siamensis DMKU-WBL1-3 that are worthy of further study.

• 터널과지하공간
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• 제10권4호
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• pp.544-552
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• 2000

노르웨이의 지질은 굳은 기반암, 높은 산악, 깊은 계곡과 피요르드로 특징 지울 수 있으며 이러한 지질학적 특성을 배경으로 많은 터널과 암반공동이 개발되었다. 터널 굴착에 종사하는 근로자들의 인건비가 매우 높음에도 불구하고 노르웨이는 이러한 터널과 암반공동의 건설에서 세계에서 가장 높은 경쟁력을 유지하고 있다. 기반암이 견고하다는 지질적인 장점 외에도 노르웨이가 저렴한 가격으로 굴착을 할 수 있는 요인은 무지보압력수로 터널, 압기완충공동, 수중관통발파와 같은 암반굴착기술의 혁신과 합리적인 계약체계, 축적된 경험으로부터 발전된 효율적인 작업 팀의 구성 및 작업방식 등이다. 본 논문에서는 지하공간 활용을 증대시킬 목적으로 노르웨이의 굴착기술을 분석하였다.

• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 2001년도 The Pacific Aisan Confrence On Intelligent Systems 2001
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• pp.211-218
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• 2001

This paper introduces a method of constructing expert systems in an integrated environment for automatic software design. This integrated environment may be applicable from top-level system architecture design, data flow diagram design down to flow chart and coding. The system is integrated with three CASE tools, FSD (Functional Structure Diagram), DFD (Data Flow Diagram) and structured chart PAD (Problem Analysis Diagram), and respective expert systems with automatic design capability by reusing past design. The construction way of these expert systems is based on systematic acquisition of design knowledge stemmed from a systematic design work process of well-matured developers. The design knowledge is automatically acquired from respective documents and stored in the respective knowledge bases. By reusing it, a similar software system may be designed automatically. In order to develop these expert systems in a short period, these design knowledge is expressed by the unified frame structure, functions of th expert system units are partitioned mono-functions and then standardized components. As a result, the design cost of an expert system can be reduced to standard work procedures. Another feature of this paper is to introduce the integrated environment for automatic software design. This system features an essentially zero start-up cost for automatic design resulting in substantial saving of design man-hours in the resulting in substantial saving of design man-hours in the design life cycle, and the expected increase in software productivity after enough design experiences are accumulated.

• 한국산학기술학회논문지
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• 제12권1호
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• pp.474-485
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• 2011

본 연구에서는 GIS(Geographic Information System) 소프트웨어의 품질을 평가하기 위해 10개의 GIS 소프트웨어에 대한 평가사례를 조사한 결과로 GIS 소프트웨어의 품질수준지표를 나타냈다. 이를 기반으로 GIS 소프트웨어 시험 사례의 축적된 결함 데이터의 분석을 통해 결함 개선비용에 관한 분석을 하였다. 이를 통해 품질에 대한 투자와 효과를 측정하여 품질확보에 필수적인 비용을 정량적으로 산출함으로써, 기업 또는 산업 단위의 품질투자의 당위성을 홍보하는데 적극 활용할 수 있는 결과를 도출하고자 한다.

• Architectural research
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• 제8권1호
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• pp.77-84
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• 2006

In spite of enormous increase in data generation, its practical usage in the construction sector has not been prevalent enough compared to those of other industries. The author would explore the obstacles against efficient data application in the arena of expenditure forecasting, and suggest a forecasting method by applying Case-based Reasoning (CBR). The newly suggested method in the research, enables project managers to forecast monthly expenditures with less time and effort by retrieving and referring only projects of a similar nature, while filtering out irrelevant cases included in database. Among 99 projects collected, the cost data from 88 projects were processed to establish a new forecasting model. The remaining 10 projects were utilized for the validation of the model. From the comprehensive study, the choice of the numbers of referring projects was investigated in detail. It is concluded that selecting similar projects at 12~19 % out of the whole database will produce a more precise forecasting. The new forecasting model, which suggests the predicted values based on previous projects, is more than just a forecasting methodology; it provides a bridge that enables current data collection techniques to be used within the context of the accumulated information. This will eventually help all the participants in the construction industry to build up the knowledge derived from invaluable experience.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.511-520
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• 2008

The steel pipe strut for a means of the retaining structure has been used generally in North America, Europe and China so far. However, Korea and Japan, two countries are much familiar with H-shape steel strut having its anisotropic strength on two different axes(named as strong and weak axes), even though they recognize the steel pipe's excellence of structural function associated with its compressive ability. This trend is mainly due to a number of its field application, accumulated know-hows and workmanship etc. This paper introduces particular features of a high-strength steel pipe strut in comparison with the H-shape steel strut and its application for two excavation sites in Seoul. As a result of field verification, the high-strength pipe steel strut is more effective than the H-shape steel strut in terms of construction costs, schedules, constructibility and structural stability.

• 한국조경학회지
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• 제33권2호
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• pp.111-121
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• 2005

The Seoul Housing Corporation pronounced an alternative design competition and a bidding for Eunpyeong New Town in December of 2004. At first many construction companies were interested in the first New Town Project. But at last a few companies had proposed the alternative design and construction cost. This project needed a conjunction of design ideas and technology know-hows. And the client wanted the brand power of construction company. Ultimately the Corporation hoped that the first New Town Project will end up with high quality successfully. This competition had started with the original construction drawings. Then it needed some alternative ideas and the lowest cost. There were two drawings of non changeable part and changeable part. Non changeable parts are structure like housing unit plan, underground parking lots. Changeable parts are outdoor layout, interior design and building facade. So we tried all ideas of landscape technology and design principles within limited guidelines. The author applied new technology like tilted rooftop greening and sustained container greening on high-rise apartment house. This green technology will be the first trial in Seoul and in the world as well. Daewoo Corporation have accumulated greening technology through the researches by national funding since 2002. Through this New Town Project the green technology will go forward step by step.

• 한국사회복지학
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• 제46권
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• pp.7-36
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• 2001

The current benefit expenditure of National Pension Scheme is comparatively small, as it stands in the early stage in reference to the historical development. On the other hand, the current contribution rate of National Pension is set up beyond which is sufficient to cover the current benefit expenditure. Therefore, National Pension makes big surplus every year such that the size of accumulated fund increases very fast. Nevertheless, the apprehension of financial instability of National Pension prevails these days. If so, is it really well-grounded? In terms of the method of financing. public pension schemes of most of all nations in the world are based on pay-as you go or partial funding. Under these financing methods, financial soundness fundamentally depends on the power that the government is able to impose the burden which is equivalent to benefit expenditure and the attitude of the public which represents whether they will admit it or not. Under this perspective, the judgement of financial soundness of public pension can not be made arithmetically and technically only on the basis of the balance between receipts and expenditure but should be accomplished considering the very complex and diverse aspects. In these context, this paper defines what the financial soundness of public pension means specifically and presents the objective indices which help judge it, that is, implicit debt, cost rate, summarized cost rate, pension expenditure as percentage of GDP, and fund rate. Then, applying the indices, this paper analyzes the long-term financial situation of National Pension empirically and evaluates its financial soundness in exploratory perspective.

• Advances in pediatric surgery
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• 제9권1호
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• pp.41-44
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• 2003

Appendicitis is the most common surgical emergency in childhood. Open appendectomy has been the standard treatment. The minimally invasive techniques have been adopted in children after experiences in various surgical conditions in adults has accumulated. It is debatable whether laparoscopic appendectomy (LA) is superior to open appendectomy (OA) in children. The goal of this study is to review the results of laparoscopy and laparotomy in the nonperforated appendicitis. The records of 22 patients under 15 years of age who were operated upon for nonperforated appendicitis at Asan Medical Center were analyzed between December 2002 and April 2003. Age, type and length of intervention, frequency of analgesic use, complication, length of hospitalization, and cost for each treatment groups (N=11) were compared. Laparoscopy patients were older (13.0 vs. 10.1 years; p > 0.05), and operative time was longer (55.0 vs. 35.0 minutes; p < 0.05). There was no conversion (OA to LA). The median length of hospital stay was significantly shorter in laparoscopy (3.0 vs. 2.0 days; p < 0.05). The median cost for LA was more expensive (W833, 836 vs. W751,398; p < 0.05). Even though there were higher costs and longer operative times with laparoscopic procedures, the shorter hospital stay was an advantage.