무선 채널 STATE 모델 개발에 관한 연구

한재충,정창환 명지대학교 산업기술연구소 2001 産業技術硏究所論文集 Vol.20 No.-

It is crucial to analyse the wireless channel environment on developing the wireless communication system. Current wireless system, i.e., PCS or IMT-2000, was highly effected on Rayleigh fading, for using the high frequency bandwidth around 2GHz. This thesis will investigate the characteristic of Rayleigh fading channel, and develop a State model which enable to analyse the fading channel. We will develope the Finite-State Markov Model that is compensated for disadvantage of Gilbert Model and Hidden Markov Model(HMM) using now. This thesis also verify the efficiency of the developed State model using computer simulation.

치근단 병소를 가진 치아의 발치 후 즉시 임플란트 식립 및 보철을 통한 심미성 회복

이재영,김지환,한동후 大韓齒科補綴學會 2012 대한치과보철학회지 Vol.50 No.3

Esthetics is important in restoring maxillary anterior area. Alveolar bone resorption and loss of interdental papilla may be minimized by immediate implantation. Previous studies showed successful results with the immediate implantation in healthy extraction socket, while many of these studies objected the immediate implantation into extraction sites with periapical lesions. Recent studies, however, reported successful results of the immediate implantation into extraction sites with periapical lesions with careful debridement of extraction sockets and general medication of antibiotics prior to implantation. A 73-year-old female visited the department of Prosthodontics in ○○ University Dental Hospital with the chief complaint of fallen post-core and crown on left maxillary incisor. Although the incisor was with vertical root fracture and periapical lesion, the immediate implantation following the extraction of tooth was planned. Thorough socket debridement, irrigation with chlorhexidine, and tetracycline soaking were followed by immediate implantation. The general medication of antibiotics (Moxicle Tab, 375 mg) was prescribed before and after the surgery. Immediate provisional restoration was delivered two days after the surgery, and the definitive metal-ceramic restoration was placed about six months later after reproducing the emergence profile from the provisional restoration. This case presents satisfying result esthetically and functionally upto two years after the placement of prosthesis with the harmonious gingival line and no loss of marginal bone. 상악 전치부는 심미적 회복이 강조되는 부위다. 발치 후 치유될 때까지 기다린다면 치조골 흡수와 치간 유두 수축을 방지할 수 없다. 일단 흡수된 조직을 재생하기 위해서는 추가적인 외과적 술식이 필요하고 치료 기간도 많이 소요된다. 발치 전 치조골과 치은 조직이 건강하다면 치주 조직을 보존 유지하기 위해 발치와 동시에 즉시 임플란트 식립을 고려할 수 있다. 특히 건전한 발치와에서의 즉시 임플란트 식립은 여러 논문에서 성공적인 결과를 보였다. 치근단 병소가 존재하는 치아의 발치 후 즉시 임플란트 식립에 대해서는 부정적인 반응을 보이는 연구가 많았으나, 최근에는 확실한 발치와의 육아조직제거와 전신적 항생제 투여 시 성공률이 높다는 결과도 보고되고 있다. 본 증례는 73세 여환으로 상악 좌측 중절치의 포스트-코어와 금속도재관이 탈락되었으며 임플란트 치료를 받고 싶다는 주소로 내원하였다. 치근단 병소와 수직적 치근 파절이 존재하였으나 치근단 병소가 있는 치아에서도 즉시 임플란트 식립의 성공사례가 여러 차례 보고되어 발치 및 즉시 임플란트 식립을 계획하였다. 발치 후 발치와 육아조직제거와 클로르헥시딘 용액 소독 및 tetracycline 용액으로 soaking을 시행한 후 임플란트를 식립하였으며 식립 전 후로 전신적 항생제를 투여하였다. 임플란트를 식립하면서 인상채득하여 2일 뒤 임시 보철물을 장착하였다. 약 6개월 뒤 치경부 형태를 재연하여 최종 인상 채득하였으며 최종 보철물을 장착하였다. 보철물 장착 후 2년까지 치은선이 인접치아와 조화를 이루고 변연골 흡수없이 심미적으로 만족할만한 결과를 얻었기에 보고하는 바이다.

PVA-ECC를 활용한 Half PC 복합체의 역학적 특성에 관한 실험적 연구

김재환,김영덕,김갑수,조봉석,장종호,김무한 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.2

ECC represents one particular class of HPFRCC, which are defined by an ultimate strength higher than their first cracking strength and the formation of multiple cracking during the inelastic deformation process. This study is to provide the fundamental data for the development of hybrid construction method such as the half PC(Precast concrete) reinforced by PVA-ECC, the mechanical properties of half PC according to the alteration of properties of PVA-ECC in terms of the type of fiber, Vr, S/M, placing height of PVA-ECC, are experimentally investigated. As the results. it is found that the half PCs of PVA-ECC have very higher mechanical performance in terms of yield load, strain capacity beyond yield point and maximum flexural load than that of mortar. Also, flexural crack in the half PCs of PVA-ECC are not localized at first crack and are growed to many micro crack, especially multiple cracking in specimen of P(12)-30-0.1ㆍ3 occurred.

3전극형 정전하 중화장치 기초연구

鄭石煥,韓昌陰,李大熙,文在德 경북대학교 센서기술연구소 1998 센서技術學術大會論文集 Vol.9 No.1

Methods and systems to remove static electricity are requested necessarily because the static electricity causes a flammable gas explosion, a fire, reduction of production rate in manufacturing semiconductor device and so on. This paper deals with the new structure of electrode to protect dusts attached to the needle electrode previously for controlling the quantities of generated ions and solving the problem of dust attaching to needle electrode. And the discharge system with third electrode was proposed to control the hight and electric field in end of needle electrode. It was possible to control the quantities of generated ion by controlling electric field in needle electrode. This showed the possibilities to solve the nonequilibrium of generated ions when using the ac power source.

한국지점 우량에 대한 확률강우량 산정에 관한 연구

이원환,김재한 연세대학교 산업기술연구소 1975 논문집 Vol.6 No.1

본 연구는 한국내 6개 지점에서 각각 25개 降雨期間의 地點雨量 資料集團을 대상으로 適正分布型 說定과 確率降雨量 算定方法을 연구하고 地點降雨의 水文統計的 特性을 밝힌 것이다. 대상 자료집단은 기본자료집단 150개와 5개 종류의 變數變換法으로 얻어지는 750개 變量集團을 合한 900개 자료집단들에 대하여 또다시 2개 종류의 階級區分法을 적용하여 작성된 總計 1,800개 자료집단에 달하다. 각 기본자료집단의 適正分布型을 設正하기 위하여 상술한 1,800개 자료집단들을 有意水準 5%로서 χ²-test method 로서 適合度 檢定을 실시하였다. 이상의 절차로서 얻어진 각 기본자료집단들의 適正分布型에 의거한 임의의 耐用安全値(耐用年數와 耐用安全率)를 고려한 경우의 確率降雨量을 구하는 方法을 解析的 方法(Y∼k method and ??∼Y method)과 圖式的 方法(Y∼k 相關圖 및 耐用安全率別 耐用年數 Tp와 再現期間 Tr, 相關圖를 개발하였음)으로 究明하여 提案하였다.

가축분뇨 비료성분 부하수준을 고려한 지역별 적정사육두수 설정

김재환,박치호,한정대,박백균 한국농업정책학회, 한국축산경영학회 2001 농업경영정책연구 Vol.28 No.2

In relation to pollution load, 166 towns and cities set the following optimum number of livestock, according to cultivated area, the amount of fertilizer ingredient for crops and wastes. According to the analysis of the total capacity for waste based on cultivated area and fertilizer requirement, N was 279,884 M/T, P2O5 140,464 M/T and K2O 182.559 M/T. Total amount of nutrient production according to the number of livestock were 222,331 M/T N, 64,716 M/T P2O5 and 86,670 M/T K2O, which are 86.7%, 53.6% and 52.7% of the fertilizer requirment. It is estimated that 45 regions showed an overload capacity of fertilizer per hectare in N, 11 regions in P2O5 and 13 regions in K2O, The converted optimum number of livestock was 13,415,000 Livestock Unit (LU).

물시멘트비 및 단위수량에 따른 고품질 재생잔골재를 사용한 재생콘크리트의 공학적 특성에 관한 실험적 연구

문형재,송민섭,김재환,장종호,김용로,김무한 대한건축학회 2004 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.24 No.1(구조계)

The purpose of this study is to investigate and analyze experimentally and positively engineering properties of recycled concrete using high quality recycled fine aggregate according to w/c ratio and unit water contents. And it is intend to present fundamental data for the mix design and the improvement of quality. The results are as follows; According to the increase of W/C ratio, the addition ratio of superplasticizer was reduced, the strength of compressive and tensile showed low and carbonation depth and chloride penetration depth showed high. And according to the increase of unit water contents, the addition ratio of superplasticizer was reduced, the strength of compressive and tensile showed low and carbonation depth and chloride penetration depth showed high.

캔터키 블루그래스에 의한 잔디 조성 기술 개발

이재필,조용인,서한용,이상재,김태준,한인송,김두환 建國大學校附設農業資源開發硏究所 2001 農資源開發論集 Vol.23 No.-

Seed sowing is the major method for the establishment of cool-season grasses at the soccer fields, golf courses, etc. Germination speed of kentucky bluegrass(Poa prantensis L.: KB) is much slower than the other cool-season grasses. This study was conducted to solve the problems at the early stage of establishment with KB. The best priming conditions of KB, drying method after soaking in the water, and covering materials will be selected. To reduce irrigation frequency and quantity for seed germination, seeds of KB were exposed to the different soaking temperature(4, 20, 25, 30℃). soaking durations(3, 6, 10, 13, 19, 23 days), storage periods(3, 6, 9 days), storage humidities(30, 50, 100%), shading rate(0, 50, 100%), drying methods(dry in the air, heating, mix soaked seed with profile=1:2), and covering materials(70% shade net, fiber net). The optimum soaking temperature and duration for the seed priming of KB were 20℃ and 10 days, respectively. The optimum storage period and humidity were 3 days and 100%, respectively, Under 50% shading, germination rate was the highest. In drying method after soaking, mixture of seeds and profile(1:2) was optimum for sowing. Using the thin fiber net as covering material after sowing was good for not moving seeds and improved germination speed and rate.

茂朱 南大川 上流水系 汚染이 本流의 水質에 미치는 影響에 關한 硏究

金煥基,崔頭炯,韓雄在 全北大學校 附設 都市및環境硏究所 1996 都市 및 環境硏究 Vol.11 No.1

This study was investigated for the pollution load of water quality in the basin of Wondangchon. Total pollution load was measured that BOD was 683.6 ㎏/day, SS was 1,436.184 ㎏/day, T-N was 237.244 ㎏/day, and T-P was 62.078 ㎏/day respectively inthere. Furthermore, it was estimated that BOD is 1,056.863 ㎏/day, SS is 1,840.657 ㎏/day, T-N is 299,922 ㎏/day, and T-P is 74.154 ㎏/day respectively in 2006 year. In case of BOD loading, that by population accounted for 63% of all BOD loading of that, 57% was discharged in M-4 drainage area. However, since tourists have been increasing gradually, that by population was estimated to be analogous to that by tourists in 2006 year. In case of SS loading, that by livestock was bigger than that by population by holding for 49% of all SS loading, and that by tourists was 9.8% now, however, ratio of that by tourists was estimated to be increased up to 25.8% in 2006 year. In case of T-N loading, that from wastewater treatment plant located in M-1 drainage area was the biggest by accounting for 56.2%. In case of T-P loading, that by livestock discharged form M-4 drainage area accounted for 44.3% of all T-P loading, and ratio of both of that by tourists and that from wastewater treatment plant gradually was estimated to be increased From above results, showing yearly change in pollution load of each water quality items is estimated to be increased continuously in every items, and in the influence of the pollution load of each drainage area upon Muju Namdaechon, M-4 drainage area was the biggest by accounting for 45% of total pollution load, and nest was ordered to M-1, M-2, M-3 and polltion load from wastewater treatment plant. The water quality of Namdaechon in Muju influenced by the study area was in the result of BOD 17.7%, SS 13.0%, T-N 28.2% and T-P 22.9%.

내시경을 이용한 관골궁골절 정복술

박대환,이재욱,장경수,송철홍,한동길,안기영 大韓成形外科學會 1998 Archives of Plastic Surgery Vol.25 No.1

Although the zygomatic arch can be employed as a key landmark to the accurate alignment of a displaced zygoma fracture, it has been traditionally avoided because of the need for a bicoronal incision. Exposure of the zygomatic arch by means of the conventional bicoronal incision has several possible disadvantages, including an increased risk of blood loss, alopecia, loss of sensation posterior to the incision, and traction palsy of the facial nerve. Endoscopic-assisted exposure of a zygomatic arch can largely obviate the disadvantages of a bicoronal incision and yield this site accessible to reduction and internal fixation in the routine treatment of displaced zygoma fractures. 9 cases of endoscope-assisted open reduction of zygomatic arch fracture and 3 cases of internal fixation of a moderately displaced zygoma fracture are presented. To accomplish this technique, a rigid 4 mm, 30 degree down-angled endoscope, trocar and cannula, endoscopic forehead lift instrument were used. The postoperative courses were satisfactory with few complications. The use of endoscope in the treatment of zygoma reduction provided an expanded field of vision, direct manipulation of lesions, minimal postoperative scar. In particular, exposure and fixation of the zygomatic arch were performed without the need for a bicoronal incision.