차분 영상의 4대역 분할에 의한 적응 양자화 압축효과

장세봉,김태효,박영석 慶南大學校 附設 工業技術硏究所 1999 硏究論文集 Vol.17 No.-

본 논문에서는 동영상의 차분 프레임을 4개의 부대역으로 분할하고 처리하는 알고리즘을 제안하였다. 본 알고리즘은 동영상 차분 프레임을 구하고 이를 4개의 부대역으로 분할한 후 DCT 처리하게 되는데, 여기서 차분 프레임 사이에 분산 값으로 임계치를 설정하고 움직임 성분을 검출한다. 압축률을 개선하기 위해 SBDCT 및 Huffman 부호화 한다. 모의실험 결과, 0.04bit/pixel의 압축율을 얻을 수 있었다. This paper proposes a moving image compression algorithm using subband coding which divides and processes the difference frame of each moving image into 4 subband region. This method decomposes the original image with each subband and performs DCT. The moving blocks are detected from each of subband using threshold value which is select from the variance of difference between frames, then the data are performed SBDCT and Huffman coding in order to improve the compression ratio. As the result of simulation, we confirmed that this method improved the bit rate of 0.04bit/pixel from reconstructed image.

(Fe,M)-Nd-C 리본합금의 자기적 특성 (M = A1, Co, Ni)

장태석 선문대학교·중소기업기술지원연구소 1998 선문공대 연구/기술 논문집 Vol.3 No.1

소량 (2 at% 이하)의 Al, Co, Ni 첨가가 급랭응고한 강자성 Fe-Nd-C 합금의 자기특성에 미치는 영향을 조사하였다 이들은 as-spun 리본합금의 비정질환을 억제하면서 결정상의 정출을 안정화시키는 역할을 하여 연자성 Fe_17Nd_2C_x가 일차상으로 정출하였다 따라서 강자성 Fe_14Nd_2C는 열처리를 통한 고상변태에 의해 얻어졌으며, 이 상이 안정하게 존재하는 온도구역에서 15분 정도 열처리함으로서 1㎛에 훨씬 못 미치는 미세한 결정립들을 얻을 수 있었다. 일반적으로 첨가량이 증가하거나 열처리 온도가 상승하면 결정립이 조대해지는 경향을 나타내었으며, 특히 Ni를 첨가했을 때에는 grain boundary shding에 의한 결정립의 조대화가 뚜렷하게 나타났다 Al,Co, Ni 모두 첨가향이 0.5 at%일 때 보자력 향상의 효과가 가장 크게 기여한 원소는 Ni였으며, 0.5 at%를 첨가한 합금을 750℃에서 20분간 열처리하였을 때 약 14 7 kOe의 보자력을 얻을 수 있었다. 또한 소량의 Ni 첨가는 Fe_14Nd_2C의 curie 온도(0 5at% 첨가시 약 305℃)를 상승시킴으로서, 이 상의 열적 안정성도 향상시키는 효과가 있었다 Effect small Al, Co, or Ni additions (<2 at%) on the phase formation and magnetic properties of melt-spun Fe-Nd-C alloys was investigated Addition of these elements commonly suppressed the amorphization but stabilized the crystallization of as-spun ribbons, resulting in soft magnetic Fe_17Nd_2C_x as a primary phase Thus, hard magnetic Fe_14Nd_2C consisting of fine grains far less than 1㎛ could be obtained by annealing the ribbons for about 15 min at the temperature range in which Fe_14Nd_2C was stable Generally, the more the amount of addition and the higher the anncaling temperature, the grains were tended to be coarse. Especially, when Ni was added, coarsening of the grains due to the grain boundary sliding was evident In all cases, when the amount of addition was 0 5 at%, the increase of coercivities was the highest, and the coercivity decreased as the amount of addition increased. Among Al, Co, and Ni, Ni was the best chose to increase the coercivity yielding 14 7kOe from the ribbons 0 5 at% Ni was added and annealed for 20 min. at 750℃ Ni was also effective to increase the thermal stability of Fe_14Nd_2C by increasing Curie temperature of Fe_14Nd_2C (about 305℃ with 0 5 at% Ni addition)

산악해안도시지역에서 기상예측모델을 이용한 3차원 바람장의 수치모의

장은숙,엄태인 한밭대학교 생산기반기술연구소 2002 생산기반기술연구소 논문집 Vol.2 No.1

The numerical model simulation was conducted to evaluate complex wind flows over Pusan Metropolitan City, a typical mountainous coastal urban area of Korea. SAIMM(System Application International Mesoscale Model), a meteorological prediction model, includes surface heat budget and relatively detailed parameterizations of the atmospheric surface and planetary boundary layers. The experiment was carried out for August 17 to 18, 1995. The simulated daily variation of wind flows is well represented in the typical sea/land breeze and mountain/valley wind alternation in the model region with irregular topographic conditions. While the valley wind occurred before sea breeze by surface heating blows to the top of the mountain in summer morning, the speed of sea breeze which directs inland from the coast area grew stronger and strong convergence zones were formed at several valley areas of inland in the afternoon. The mixing height of inland reached approximately 1300m by ascending stream and prevailing heat convection during the day time. Compared the calculated results with the horizontal wind data observed from Automatic Weather System, the characteristics of local circulation in area studied were discussed.

하드 포인트 변경에 따른 조종안정성 평가

배태한,장석동,송철기 慶尙大學校 經營行政大學院 2004 工學硏究院論文集 Vol.20 No.-

Vehicle stability is an important subject in vehicle design and control, because vehicle stability is closely dependent upon its dynamic performance. The modeling and its analysis are performed by using ADAMS in the present paper. The camber angle and the toe angle are analyzed due to the hard point movement in the static simulation. The side slip angle and the yaw rate are analyzed due to the hard point movement in the driving simulation such as the steady state cornering and the double lane change.

무지 외반증 환자의 hard insole 착용에 의한 중족지절관절 각도의 변화

임성태,김택훈,최흥식,노정석,김장환 한국전문물리치료학회 2001 한국전문물리치료학회지 Vol.8 No.2

The purpose of this study was to investigate the effect of donning of a hard insole in patients with hallux valgus. Fourteen subjects were selected from patients with foot pain at Lee Chang-Heon Foot Clinic from August 4,2000 to September 15, 2000. The hallux valgus angle and the first-second intermetatarsal angle were radiographically measured before and after donning the hard insole. Based on these two kinds of angles, a mild hallux valgus deformity group was characterized by the hallux valgus angle of less than 20 degrees, and a moderate hallux valgus deformity group was characterized by the hallux valgus angle of 20 to 40 degrees. After three weeks with the hard insole donned, the foot angles of the patients with hallux valgus were measured again. The data were analyzed by Wilcoxon signed ranks test, and the following results were obtained: 1) After the trial, both mild hallux valgus deformity group and moderate hallux valgus deformity group demonstrated that the hallux valgus angles were significantly decreased. 2) After the trial, mild hallux valgus deformity group demonstrated that the first-second intermetatarsal angle was significantly decreased. 3) After the trial, moderate hallux valgus deformity group demonstrated that the first-second intermetatarsal angle was not significantly decreased. The above findings revealed that according to donning hard insole, the hallux valgus angles of mild and moderate hallux valgus deformity groups and the first-second intermetatarsal angle of mild hallux valgus deformity group were significantly decreased. The results of this study have some limitation for generalization due to the limited number of subjects. Further studies are needed to evaluate the effect of hard insole on hallux valgus with more precise laboratory equipments and measurements in patients with hallux valgus.

실내 기후동에서 개인형 국소냉방 장치의 기류 및 온도 분포해석

엄태인,장은숙,경남호,신기식,문승현,전영남,류창국 한밭대학교 생산기반기술연구소 2002 생산기반기술연구소 논문집 Vol.2 No.1

Numerical simulation is performed by the commercial code FLUENT for individual air condition system to calculate the velocity and temperature profiles around worker in climate room. The main calculation region is the space of ㄱ shape between wall and worker in the individual air condition system. The fresh air is emitted from 3 inlet attached on the right, left and center wall. Because the comfort of worker is closely related with the velocity and temperature of wind, these data are key role for design of the individual air condition system. This work is previous study for evaluation of thermal comfort of workers in room without much experiments according to metabolism and heat emission of human body. Numerical simulation results are as followings, 1. There is an possibility of the thermal comfort of worker is gotten worse due to the presence of dramatic change of wind velocity around worker. 2. Temperature gap exists in worker's body between top and bottom according to fresh air inlet velocity and position which is right, left and center of wall. 3. Calculation results of the skin temperature of worker are key data for evaluation of thermal comfort with experimental data in climate room. 4. Optimum condition of temperature, direction and velocity of fresh air will be obtain by numerical simulation for energy effective individual air condition system.

전분/펙틴/몬모릴로나이트 나노복합 필름의 특성 및 산소 투과도 연구

서석훈,서길수,유성구,신용섭,정세환,김성철,배광수,이태진,장상희,신부영 한국공업화학회 2003 공업화학 Vol.14 No.8

Na^(+)-MMT로부터 제조한 생분해성 전분/펙틴/몬모릴로나이트 나노복합재료의 기계적 특성, 열적 특성, 그리고 산소 투과성을 연구하였다. XRD와 TEM의 결과로부터 고분자의 삽입으로 인하여 실리케이트 층간 간격이 증가하였으며, 또한 삽입형 전분/펙틴/몬모릴로나이트 나노복합재료임을 확인하였다. 합성된 전분/펙틴/몬모릴로나이트 나노복합재료의 경우 적은 양의 MMT로부터 기계적 특성과 열적 안정성이 우수함을 보였다. 그리고 전분/펙틴/몬모릴로나이트 나노복합재료의 산소 투과성은 고분자 매트릭스에 분산되어 있는 몬모릴로나이트에 의하여 현저히 저하됨을 보여주었다. Mechanical property. thermal property. and oxygen permeability of biodegradable Pectin/Starch-montmorillonite nanocomposite, prepared with Na-MMT, have been studied X-ray diffraction and TEM experiments on polymer/silicate composite samples demonstrated that the intercalation of polymer chains leads to increase in the spacing between silicate layers. In addition, it were found that the intercalated Starch/Pectin/monotmorillonite nanocomposite were prepared. It was found that the addition of only a small amount of clay was enough to improve the thermal stability- and mechanical property of Starch/Pectin/montmorillonite nanocomposite. Oxygen permeability of Starch/Pectin/montmorillonite composite was generally lower than that of pectin/starch.

Pd 촉매하에서 allylic alcohol과 hypervalent iodine 화합물의 위치 선택적 vinylation에 관한 연구

강석구,이홍우,장수범,김태현,편성재 성균관대학교 기초과학연구소 1995 論文集 Vol.46 No.2

The formation of carbon-carbon bond by palladium-catalyzed coupling of aryl or vinyl halides with olefins, known as the Heck reaction, has become a powerful tool in organic chemistry. In the case of allylic alcohols, palladium-catalyzed reaction of organic halides usually affords β-substituted ketones or aldehydes rether than β-substituted allylic alcohols.

역행성 심정지 도관 삽입을 위한 술 중 경식도심초음파의 유용성

유미숙;최원주;김정원;박장수;김경태;김지연;어상일 인제대학교 2011 仁濟醫學 Vol.32 No.-

Background: Retrograde cardioplegia catheter (RCC) insertion is one of methods for administration of cardioplegics during cardiopulmonary bypass (CPB). However its success rate depends on only surgeon's experience. We thought the transesophageal echocardiography (TEE) can guide the R CC insertion, because TEE is commonly used for monitoring status of heart during cardiac surgery. This study was designed to evaluate the RC C insertion time by TEE guidance versus conventional method without T EE guidance. Methods: Sixty patients who were scheduled to undergo elective coronary artery bypass graft (CABG) surgery under general anesthesia were divided into groups as follows: group T [RCC insertion into coronary sinus (CS) by TEE guidance, n=30] and group C [RCC insertion into CS by conventional method, n=30]. We recorded the time of insertion of RCC in to CS in two groups. RCC insertion was done by TEE guidance in case that time was over two minutes by conventional methods in group C. Results: The overall time of RCC insertion into CS was 63.8 ± 23.6 seconds in the Group T and 102.3 ±55.7 seconds in the Group C, respectively (p=0.001). There were no complications during RCC into CS by T EE guidance. Conclusions: TEE guidance for RCC insertion into CS is shorten the time of insertion.

18–30세 사이에 발생하는 뇌경색의 특징, 다기관 레지스트리 연구

장윤경,송태진,김용재,허지회,이경열,김영은,장민욱,조수진,강석윤 이화여자대학교 의과학연구소 2017 EMJ (Ewha medical journal) Vol.40 No.3

Objectives: Although there have been several reports that described characteristics for young age stroke, information regarding very young age (18–30 years old) has been limited. We aimed to analyze demographic factors, stroke subtype, and 3-month outcome in acute ischemic stroke patient who have relatively very young age in multicenter stroke registry. Methods: We evaluated all 122 (7.1%) consecutive acute ischemic stroke (within 7 days after symptom onset) patients aged 18 to 30 from 17,144 patients who registered in multicenter prospective stroke registry, 1997 to 2012. Etiology was classified by Trial of Org 10172 in Acute Stroke Treatment criteria. Stroke severity was defined as National Institutes of Health Stroke Scale (NIHSS) and stroke outcome was defined by modified Rankin scale (mRS) at 3 months after index stroke. Results: The mean age of all included patients was 25.1±3.7 years and 76 patients (62.2%) were male. The median NIHSS at admission was 4. Considering stroke subtype, 37 patients (30.3%) had stroke of other determined etiology (SOD), 37 (30.3%) had undetermined negative evaluation (UN) and 31 (25.4%) had cardioembolism (CE) were frequently noted. After adjusting age, sex and variables which had P<0.1 in univariable analysis (NIHSS and stroke subtype), CE stroke subtype (odds ratio, 4.68; 95% confidence interval, 1.42–15.48; P=0.011) were significantly associated with poor functional outcome (mRS≥3). Conclusion: In very young age ischemic stroke patients, SOD and UN stroke subtype were most common and CE stroke subtype was independently associated with poor discharge outcome.