• 한국문헌정보학회지
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• 제26권
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• pp.213-233
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• 1994

This study measured whether subject descriptor searching and citation searching retrieve different documents for conceptual queries and methodological queries in natural science, engineering and social science. The retrieval effectiveness of two search methods was measured using as criteria, total number of documents retrieved, total number of relevant documents, overlapping and unique documents and precision ratio. The search subject was water resources and the databases used were Selected Water Resources Abstracts (SWRA) and SCISEARCH. Data were collected for 21 doctoral students working on their dissertations in the three fields of water resources. Principal findings included: 1) subject searching and citation searching each retrieved substantially equal number of documents; 2) total number of relevant documents for conceptual queries was larger than that for methodological queries, while there was a large variation among the three fields; 3) the average overlap was quite small, while citation searching yielded more unique documents than subject searching; 4) for conceptual queries, citation searching yielded a higher precision ratio than subject searching, while subject searching obtained a slightly higher precision ratio than citation searching for methodological queries ; and 5) citation searching was effective for both specific queries and broad queries if seed articles are well chosen, while subject searching only worked well for broad queries. It was further found that: 1) citation searching is not a subsidiary but a substantial retrieval method in water resources; 2) SWRA is effective for queries for engineering and SCISEARCH is appropriate for queries for natural science, while neither SWRA nor SCISEARCH work well for queries for social science; and 3) characteristics of queries affect retrieval results more than the characteristics of documents or the coverage of databases.

• 방송공학회논문지
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• 제14권6호
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• pp.721-732
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• 2009

AT-DMB(Advanced T-DMB) 시스템은 기존 T-DMB와 역호환성을 유지하면서 동일한 주파수 대역폭에서 전송률을 최대 2배로 높이기 위해 개발되었다. AT-DMB 시스템은 T-DMB의 DQPSK 변조신호에 새로운 변조가 적용된 BPSK 또는 QPSK 신호를 향상 계층으로 중첩하는 계층변조를 적용한다. AT-DMB의 계층변조에 새로 추가되는 신호는 T-DMB와 역호환성 유지 및 방송권역 축소를 최소화하기 위해 크기가 충분히 작아야하는데, 추가되는 크기가 작은 신호는 전송채널에 존재하는 페이딩에 의해 쉽게 왜곡될 수 있다. 따라서 AT-DMB의 계층변조에 새로 추가되는 신호에는 오류정정 성능이 우수한 터보 (turbo) 부호를 적용하여 채널왜곡을 보상한다. 이러한 AT-DMB 시스템의 성능검증을 위해, AT-DMB 송 수신기를 구현하여 LAB 테스트를 통해 계층변조 신호의 성상비(constellation ratio)에 따른 AT-DMB 시스템의 수신율 측정결과를 얻었고, 결과분석을 통하여 AT-DMB 시스템의 적용성을 제시하였다.

• 농촌계획
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• 제15권4호
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• pp.19-32
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• 2009

This research has a significant meaning to break from the urban ecology-oriented biotope research and realize the importance of rural landscape as a reserve area for systemizing the types of rural biotope. The results are as follows. First of all, items for classification of 16 rural biotope areas are designed and total 9 itmes in slope from spatial structural point of view and 7 items in minute-variety from functional point of view. Also, as the result of on-site research on case areas based on classified items, there are 46 types of rural biotope such as coniferous forest, hedgerow and so on. For example, it is proven that uncultivated stripe showed the most frequent emergence. As a result of cluster analysis of average linkage method between clusters, 12 clusters are classified as a clusters and 13 biotope types are re-corrected and complemented through brainstorming process and then total 12 clusters are selected as final rural biotope type groups. As a rural biotope type cluster and character analysis according to types based on on-site research and documentary survey, for example, it is analyzed that the ratio of transmissible covering ratio is 100%, the ratio of green coverage is 90% in 'woodland in cultivated area biotope type cluster'.

• 한국환경복원기술학회지
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• 제14권5호
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• pp.113-125
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• 2011

Since the government of Korea (Ministry of Environment, MOE) introduced the policy applying 'Biotope-Area-Ratio-Indicator (BARI)' to huge residential land developments which Environmental Impact Assessment (EIA) should be performed, MOE has come to have the necessity to apply the indicator concretely at the stage of Prior Environment Review System (PERS) and EIA in various types of large scale land development projects. This study was conducted with the aim of supporting the application of BARI and related decision making in various other types of EIA projects as well as residential development projects through remodeling the system to apply the indicator of the past. Through the analysis of the problems in applying the past BARI and experimental appraisals to 11 types of EIA projects, the results and implications as follows were drawn. First, it's possible to extend the range of applications of BARI, which has been applied to only residential land development project, to all kinds of projects with area-typed land use pattern out of environmental impact assessment target projects. Second, it's also possible to set a target value into which regional characteristics and differences among locational properties are reflected. In addition, it's come to be able to differentially apply the target value of BARI according to the condition of the existing site. Third, it's improved to be able to suggest a macroscopic target value at the stage of PERS and to set detailed target values in each detailed land use at the stage of EIA. The key point underlies inducing methodology to determine target values to secure more permeable land coverage ratio for detailed land use patterns at the stage of EIA by making it possible to calculate BARI of the present land cover condition of the EIA target projects.

• 산업융합연구
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• 제18권2호
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• pp.69-75
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• 2020

산업용 IoT는 비용 효율적이고 넓은 커버리지를 제공하는 무선 메쉬 네트워크에 관심이 많았다. 하지만, 무선 메쉬 네트워크는 멀티홉 환경의 심각한 성능 절하를 겪는다. 이를 극복하기 위해 메쉬 라우터에 캐시를 장착하는 연구가 많았으나 캐시 파워 소모 모델 연구는 적었다. 최근 캐시 파워 효율 기반 모델은 캐시까지 콘텐츠 전달 파워를 모두 측정했기 때문에 무선 메쉬 네트워크에서 쓰기에 부적절합니다. 본 논문은 CPU의 동작속도가 캐시 크기에 비례한다는 사실을 이용하여 캐시 적중률 기반 파워 소모 모델을 제안하고, 기존 캐시 파워 효율 기반 소모 모델과 비교하여 정확하게 측정되었다. 제안된 캐시 적중률 기반 파워 소모 모델은 산업용 IoT에서 무선 메쉬 네트워크를 구성할 시 에너지 효율적인 캐시 운용을 위한 참조 모델로 활용되길 기대합니다.

• 한국통신학회논문지
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• 제33권5C호
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• pp.351-360
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• 2008

주파수 재사용을 사용하는 셀룰러 시스템에서 단말은 셀 경계로 이동할수록 인접 셀로부터 오는 간섭 신호의 세기가 커지게 되어 낮은 신호 대 간섭 비를 갖게 되고 채널 추정 및 수신 성능이 열화되는 경향을 보인다. 각 셀에 할당된 프리앰블 파일럿이 상호 직교적인 관계이거나 disjoint한 위치에 있는 경우, 각 셀로부터의 채널을 추정하여 이를 간섭 제거에 활용할 수 있다. 도플러 확산에 의한 채널의 시간 변화율이 큰 경우에는 데이터 파일럿의 사용이 필요하나, 다수의 셀로부터 전송되는 데이터 파일럿이 모든 셀에서 동일한 위치에 배치되어 있는 경우, 간섭에 의한 영향으로 채널 추정 성능의 열화를 겪는다. 본 논문에서는 인접 셀 간섭의 영향을 고려한 의사 잡음(pseudonoise: PN) 수열이 적용된 데이터 심볼에서, 간섭 신호로 인한 성능 열화를 줄일 수 있는 채널 추정 방법을 설명하고, 셀 경계 지역에서 수신 신호 검출 성능을 평가한다. 특히 최대비 결합과 셀 간 공간 역다중화 검출 방식에 활용 시, 도플러 주파수와 간섭 신호의 세기에 따른 전송 효율을 산출하여 성능 이득을 정량적으로 제시한다.

• 한국의류학회지
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• 제25권6호
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• pp.1069-1078
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• 2001

Pattern grading is a technique used to increase or decrease the size of a garment pattern according to the measurements in a given size chart. The original pattern is graded and laid out for cutting before mass production. This study tried to classify body types for pattern grading of jacket by applying a concept of "drop"defined as the difference between chest girth and waist girth and the difference between hip girth and waist girth for pants. Data were collected through the stratified sampling method. 138 subjects were selected out of 1,290 subjects of our sample population. Findings were as follows : 1) For pattern grading of jacket, the cell with the chest girth of 96cm and the waist girth of 87cm had the highest frequency rate and body type was 87H type and the coverage of this type was 9.52%. Then, the size specification 87-96 was the center of distribution. H type had seven ones such as 72H, 75H, 78H, 81H, 84H. 87H and 90H. H type had 33 observations and frequency ratio of 26.19%. Same types could be graded up and down from the reference size for the age group. And this reference size became to the starting point for developing the grading system. 2) For pattern grading of pants, fatty types, H10 type had six ones such as 80H10. 82H10, 84H10, 86H10, 88H10 and 90H10. H10 type had 28 observations and frequency ratio of 20.29%. H6 type had 6 ones such as 84H6, 86H6, 88H6, 90H6. 92H6 and 94H6. H6 type had 27 observations and frequency ratio of 19.57%. If lower body types were classified as same ones, these types could be graded up and down proportionately.

• 대한두개안면성형외과학회지
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• 제22권5호
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• pp.260-267
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• 2021

Background: Elastic ear cartilage is a good source of tissue for support or augmentation in plastic and reconstructive surgery. However, the amount of ear cartilage is limited and excessive use of cartilage can cause deformation of the auricular framework. This animal study investigated the potential of periosteal chondrogenesis in an ear cartilage defect model. Methods: Twelve New Zealand white rabbits were used in the present study. Four ear cartilage defects were created in both ears of each rabbit, between the central artery and marginal veins. The defects were covered with perichondrium (group 1), periosteum taken from the calvarium (group 2), or periosteum taken from the tibia (group 3). No coverage was performed in a control group (group 4). All animals were sacrificed 6 weeks later, and the ratio of neo-cartilage to defect size was measured. Results: Significant chondrogenesis occurred only in group 1 (cartilage regeneration ratio: mean±standard deviation, 0.97±0.60), whereas the cartilage regeneration ratio was substantially lower in group 2 (0.10±0.11), group 3 (0.08±0.09), and group 4 (0.08±0.14) (p= 0.004). Instead of chondrogenesis, osteogenesis was observed in the periosteal graft groups. No statistically significant differences were found in the amount of osteogenesis or chondrogenesis between groups 2 and 3. Group 4 showed fibrous tissue accumulation in the defect area. Conclusion: Periosteal grafts showed weak chondrogenic potential in an ear cartilage defect model of rabbits; instead, they exhibited osteogenesis, irrespective of their embryological origin.

• Journal of Yeungnam Medical Science
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• 제38권3호
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• pp.225-230
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• 2021

Background: We aimed to analyze the effectiveness of albumin to globulin ratio (AGR) in predicting postoperative febrile urinary tract infection (fUTI) after ureteroscopic lithotripsy (URS) and retrograde intrarenal surgery (RIRS). Methods: From January 2013 to May 2018, 332 patients underwent URS and RIRS. The rate of postoperative fUTI and risk factors for postoperative fUTI were analyzed using logistic regression. Patients were divided into postoperative fUTI and non-postoperative fUTI (non-fUTI) groups. AGR with other demographic and perioperative data were compared between the two groups to predict the development of fUTI after URS. Results: Of the 332 patients, postoperative fUTI occurred in 41 (12.3%). Preoperative pyuria, microscopic hematuria, diabetes mellitus, hypoalbuminemia, and hyperglobulinemia were more prevalent in the fUTI group. Patients in the fUTI group had larger stone size, lower preoperative AGR, longer operation time, and longer preoperative antibiotic coverage period. In a multivariable logistic analysis, preoperative pyuria, AGR, and stone size were independently correlated with postoperative fUTI (p<0.001, p=0.008, and p=0.041, respectively). Receiver operating curve analysis showed that the cutoff value of AGR that could predict a high risk of fUTI after URS was 1.437 (sensitivity, 77.3%; specificity, 76.9%), while the cutoff value of stone size was 8.5 mm (sensitivity, 55.3%; specificity, 44.7%). Conclusion: This study demonstrated that preoperative pyuria, AGR, and stone size can serve as prognostic factors for predicting fUTI after URS.

• 한국지반환경공학회 논문집
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• 제14권12호
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• pp.53-60
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• 2013

본 연구에서는 장기식생이 가능한 전면 식생형 보강토 옹벽의 식생 환경 적합성을 모니터링하고, 전면벽체 표면온도 측정을 통해 한여름철의 콘크리트 옹벽 전면벽체의 온도 변화를 평가하였다. 이를 위해 장기식생이 가능하도록 식생 포대를 삽입한 특수 블록 벽체를 시공하여 구절초, 맥문동을 포함한 20여 종의 종자 식재 후 2년간 식생 환경을 관찰하였을 뿐만 아니라, 실제 크기의 식생 옹벽을 건설하여 한여름철 식생 및 무식생 옹벽의 전면벽체 표면온도를 비교 분석하였다. 식생 환경 모니터링을 수행한 결과, 장기 식생이 가능한 블록 내에 식재된 대부분의 식물 생장 상태는 양호한 것으로 나타났으며, 식생 포대를 삽입한 블록 벽체가 식물의 성장에 적합한 환경을 제공하는 것으로 나타났다. 또한, 한여름철의 식생 옹벽과 무식생 옹벽의 콘크리트 블록 표면의 온도 변화량을 측정한 결과, 식생 옹벽에 비해 무식생 옹벽의 표면온도가 높게 나타났다. 식생 옹벽의 전면벽체의 경우, 무식생 옹벽의 전면벽체에 비해 표면온도 증가율이 작게 나타난 반면, 냉각율은 더 크게 나타나 장기식생이 가능한 전면 식생형 보강토 옹벽은 식생을 통해 열섬효과를 완화하는데 효과적으로 작용할 수 있을 것으로 판단된다.