• Journal of Korean Neurosurgical Society
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• 제52권3호
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• pp.234-239
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• 2012

Objective : Chronic subdural hematoma (CSDH) is a typical disease that is encountered frequently in neurosurgical practice. The medications which could cause coagulopathies were known as one of the risk factors of CSDH, such as anticoagulants (ACs) and antiplatelet agents (APs). Recently, the number of patients who are treated with ACs/APs is increasing, especially in the elderly population. With widespread use of these drugs, there is a need to study the changes in risk factors of CSDH patients. Methods : We retrospectively reviewed 290 CSDH patients who underwent surgery at our institute between 1996 and 2010. We classified them into three groups according to the time of presentation (Group A : the remote period group, 1996-2000, Group B : the past period group, 2001-2005, and Group C : the recent period group, 2006-2010). Also, we performed the comparative analysis of independent risk factors between three groups. Results : Among the 290 patients, Group A included 71 patients (24.5%), Group B included 98 patients (33.8%) and Group C included 121 patients (41.7%). Three patients (4.2%) in Group A had a history of receiving ACs/APs, 8 patients (8.2%) in Group B, and 19 patients (15.7%) in Group C. Other factors such as head trauma, alcoholism, epilepsy, previous neurosurgery and underlying disease having bleeding tendency were also evaluated. In ACs/APs related cause of CSDH in Group C, significantly less proportion of the patients are associated with trauma or alcohol compared to the non-medication group. Conclusion : In this study, the authors concluded that ACs/APs have more importance as a risk factor of CSDH in the recent period compared to the past. Therefore, doctors should prescribe these medications carefully balancing the potential risk and benefit.

• 한국콘텐츠학회논문지
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• 제11권6호
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• pp.51-58
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• 2011

무선 센서 네트워크의 라우팅 기술은 제한된 에너지를 갖고 있는 센서 노드들의 에너지 수명을 최대한으로 연장할 수 있는 방법으로 많이 연구되고 있다. 기본 라우팅 방법 중 위치 정보를 이용한 라우팅 방법은 라우팅 설정을 위한 계산시에 필요한 정보의 양이 평면, 계층적 라우팅 방법보다 적기 때문에 효율적이다. 하지만 주로 거리를 활용하기 때문에 센서 노드의 에너지 활용도가 떨어질 수도 있다. 본 논문에서는 최적의 경로 탐색에 많이 이용되고 있는 개미 집단 시스템(ACS : Ant Colony System)의 전이 확률에 센서의 에너지양과 싱크와의 거리를 이용한 가중치를 부여하여 무선 센서 네트워크의 에너지 사용량을 고르게 사용할 수 있게 하였다. 제안된 방법은 대표적인 GPSR(Greedy Perimeter Stateless Routing)과 비교하여 에너지 사용도에 있어 평균적으로 46.80%의 향상을 보였으며, 기존의 ACS보다 동일한 시간의 수행 종료 후 잔여 에너지가 평균 6.7% 더 남아 있음을 확인하였다.

• 정보처리학회논문지B
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• 제10B권7호
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• pp.751-756
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• 2003

개미 집단 최적화는 최근에 제안된 조합 최적화 문제를 해결하기 위한 메타 휴리스틱 탐색 방법으로, 그리디 탐색뿐만 아니라 긍정적 반응의 탐색을 사용한 모집단에 근거한 접근법으로 순회 판매원 문제를 풀기 위해 처음으로 제안되었다. 본 논문에서는 기존의 개미 집단 시스템의 성능을 향상시키기 위해 강화와 다양화를 통한 집단간 긍정적 상호작용과 부정적 상호작용을 수행하는 다중 집단 개미 모델을 제안한다. 이 알고리즘은 TSP 문제를 해결하기 위해 몇 개의 에이전트 집단으로 이루어진 ACS 집단간의 상호작용을 통해 문제를 해결하는 방법이다. 본 논문에서는 이 제안된 방법을 TSP 문제에 적용해 보고 그 성능에 대해 기존의 ACS 방법과 비교 평가해, 문제 해결의 질적 수준이 우수하다는 것을 실험을 통해 알아보고자 한다.

• 천문학회보
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• 제42권1호
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• pp.29.1-29.1
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• 2017

I present new near-infrared (NIR) photometry of globular cluster (GC) systems associated to a cD galaxy NGC 4874 in the core of the Coma cluster and 16 early-type galaxies in the Fornax and Virgo clusters of galaxies using the Infrared Channel of the Wide Field Camera 3 (WFC3/IR) on board the Hubble Space Telescope (HST). Combining these high-resolution NIR data with new HST Advanced Camera for Surveys (ACS) optical photometry for NGC 4874 and existing ACS GC catalogs from the ACS Fornax and Virgo Cluster Surveys, I have examined for the first time the GC systems in a statistically significant optical/NIR sample of galaxies spanning a wide range of luminosities and colors. A primary goal of this study is to explore empirically whether the distributions of purely optical and hybrid optical - NIR color indices for extragalactic GCs have different forms and whether the relations between these color indices are nonlinear, indicating that they behave differently with underlying metallicity. I find that some GC systems of large galaxies in our sample show color bimodalities that differ between the optical and optical - NIR colors, in the sense that they have disparate ratios of "blue" and "red" peak GCs, as well as differing ratios in their color dispersions. Consistent with these results, I find empirically that the dependence of hybrid optical-NIR color on purely optical color is nonlinear, with an inflection at intermediate metallicities. These findings underscore the importance of understanding the nature of galaxy-to-galaxy variations in the GC color distributions and color-color relations, as well as the exact forms of the color-metallicity transformations, in interpreting the observational data on GC color bimodality. Our ACS data for NGC 4874 shows that its GC system exhibits a very strong blue tilt, implying a very steep mass-metallicity scaling, and the centroid of this GC system is offset by $4{\pm}1kpc$ from the luminosity center of NGC 4874, in the direction of NGC 4872. Finally, I discuss the asymmetrical GC distribution around a dwarf elliptical galaxy in Coma that has a very high relative velocity with respect to the cluster mean at small clustercentric radius.

• Korean Chemical Engineering Research
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• 제44권6호
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• pp.644-649
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• 2006

본 연구에서는 다양한 조건에서 기체상태의 오존처리된 활성탄소를 이용하여 수용액 상태에서의 Cr(VI)의 흡착특성에 대하여 고찰하였다. 오존처리된 활성탄소의 표면특성의 변화는 pH, 산도-염기도, FT-IR을 이용하였으며, $N_2$/77K 등온 흡착특성은 BET식, Boer의 t-plot, 그리고 Horvath-Kawazoe의 slit pore model을 이용하여 확인하였다. 또한, 총 Cr의 흡착량은 ICP-AES를 이용하여 확인하였다. 실험 결과, 오존처리는 활성탄소의 표면에 산소를 함유한 극성 관능기를 증가시켰으며, 이로 표면산도 또한 증가되었다. 한편, 오존처리의 영향으로 보이는 활성탄소의 비표면적과 미세기공 부피의 감소가 관찰되었지만, 활성탄소의 총 Cr 흡착량은 오존처리 시간이 증가할수록 비례적으로 증가하였다. 이는 활성탄소의 Cr 흡착특성이 비표면적보다 상대적으로 표면에 형성된 극성 관능기의 영향을 크게 받는 것으로 판단된다.

• Reproductive and Developmental Biology
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• 제28권2호
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• pp.89-94
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• 2004

본 연구는 생쥐 자궁에 있어서 아라키돈산으로부터 prostaglandin의 생성에 관여하는 것으로 추측되는 acyl-CoA sytnhetase 4 유전자의 임신단계별 발현을 확인하고자 실시하였다. Acyl-CoA sytnhetase 4 유전자는 착상 전에는 발현이 증가하는 경향을 나타내었으며 착상 후에는 감소하였다. 이러한 발현의 양상은 세포막의 인질로부터 아라키돈산을 유리시키는 cPLA2의 발현과 유리된 아라키돈산으로부터 prostaglandin의 생성에 관여하는 COX1과 COX2의 발현 양상과 일치하였다. 이러한 결과는 세포막에서 유리된 아라키돈산이 무한적으로 COX1과 COX2에 의하여 prostaglandin의 생성에 이용되는 것이 아니라 acyl-CoA sytnhetase 4에 의하여 세포막의 인지질로 되돌려져 prostaglandin의 생성을 조절하는 기능을 세포가 수행하고 있는 것으로 추정된다.

• Clinics in Shoulder and Elbow
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• 제24권3호
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• pp.172-177
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• 2021

Background: This study aimed to evaluate the response rate to arthroscopic release treatment in adhesive capsulitis of the shoulder (ACS) for patients with refractory to conservative treatment. Methods: In this retrospective study, 51 patients (age mean, 49.1±5.6 years) with unilateral adherent capsule underwent arthroscopic releasing surgery for the shoulder capsule. Etiologies of the ACS in 30 patients were idiopathic: 10 patients were affected after surgery and 11 patients following trauma. The patients were evaluated in terms of shoulder function, satisfaction rate, pain intensity, and joint range of motion (ROM) based on a Constant score, a Simple Shoulder Test, the visual analog scale, and four movements, respectively. Results: The mean Constant score before surgery was 48.2±3.5 and reached 74.4±6 and 77.0±6.3 at 6 months and the final follow-up, respectively (p<0.001). The mean scores of pain intensity, a Simple Shoulder Test, and ROM showed significant improvement at all follow-ups (p<0.001). Sex, age, and diabetes did not have any significant effect on patient recovery. However, patients who experienced ACS after surgery had poorer results than others at all follow-up points. Conclusions: Arthroscopic releasing surgery of the shoulder in patients with ACS refractory to conservative treatment produces rare complications and an effective injury response. It seems that patients suffering ACS following surgery have a weaker response to the treatment.

• Journal of Periodontal and Implant Science
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• 제33권3호
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• pp.457-474
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• 2003

The ultimate objective of periodontal treatment is to get rid of an on-going periodontal disease and further regenerate the supporting tissue, which is already destroyed, functionally. Currently, the bone grafting operation using various kinds of bone grafting materials and the operation for induced regeneration of periodontal tissue using the blocking membrane are performed for regeneration of the destroyed periodontal tissue. However, there are respective limitations Galenical preparations, which are used for regeneration of periodontal of tissue, has less risk of rejective reaction or toxicity that may be incidental to degradation and their effect is sustainable. Thus, in case they are applicable to a clinic, they can he used economically. Chitosan has such compatibility, biological actions including antibacterial activity, acceleration of wound treatment, etc., and excellent mechanical characteristics, which has recently aroused more interest in it. Also, it has been reported that it promotes osteogenesis directly or indirectly by functioning as a matrix to promote migration and differentiation of a specific precussor cell (for example, osteoblast) and further inhibiting the function of such a cell as fibroblast to prevent osteogenesis. In this study, the pure chitosan solution, which was obtained by purifying chitosan, was used. However, since this chitosan is of a liquiform, it is difficult to sustain it in a defective region. It is, therefore, essential to use a carrier for delivering chitosan to, and sustaining it gradually in the defective region. In the calvarial defect model of the Sprague-Dawley rat, it is relatively easy to maintain a space. Therefore, in this study, the chitosan solution with which ACS was wetted was grafted onto the defective region, For an experimental model, a calvarial defect of rat m s selected, and a critical size of the defective region was a circular defect with a diameter of 8 mm. A group in which no treatment was conducted for the calvarial defect was set as a negative control group. Another group in which treatment was conducted with ACS only was set as a positive control group (ACS group). And another group in which treatment was conducted was conducted with by grafting the pure chitosan solution onto the defective region through ACS which was wetted with the chitosan solution was set an experimental group (Chitosan/ACS group). Chitosan was applied to the Sprague-Dawley rat's calvarial bone by applying ACS which was wetted with the chitosan solution, and each Sprague-Dawley rat was sacrificed respectively 2 weeks and 8 weeks after the operation for such application. Then, the treatment results were compared and observed histologically and his tometrically. Thereby, the following conclusions were obtained. 1. In the experimental group, a pattern was shown that from 2 weeks after the operation, vascular proliferation proceeded and osteogenesis proceeded through osteoblast infiltration, and at 8 week after the operation, ACS was almost absorbed, the amount of osteogensis was increased and many osteoid tissue layers were observed. 2. At 2 weeks after the operation, each amount of osteogenesis appeared to be 8.70.8 %, 13.62.3 % and 4.80.7 % respectively in the experimental group, the positive control group and the negative control group. Accordingly, it appeared to be higher in the Experimental group and the positive control group than in the negative control group, but there was no significant difference statistically (p<0.01). 3. At 8 weeks after the operation, each amount of osteogenesis appeared to be 62.26.1%, 17.42.5 % and 8.21.4 % respectively in the experimental group, the positive control group and the negative control group. Accordingly, it appeared to be substantially higher in the experimental group than in the positive control group and the negative control group, and there was a significant difference statistically (p<0.01). As a result of conducting the experiment, when ACS was used as a carrier for chitosan, chitosan showed effective osteogenesis in the perforated defective region of the Sprague-Dawley rat's calvarial bone.

• 생명과학회지
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• 제18권9호
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• pp.1263-1270
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• 2008

본 연구는 심장재활에 참여한 고혈압을 동반한 급성관상동맥질환자중 내과적인 약물로 조절되지 않은 고혈압 환자의 경우와 약물로 조절되는 정상 혈압 환자군에서 트레드밀 운동과 고정식 자전거 운동 수행시 강도별 혈압과 심근산소소비량, 자각지수에 대한 반응을 구명(究明)하고자 목적하였다. 이를 위해 6주간의 심장재활 프로그램에 참여한 심혈관질환 환자를 연구대상으로 약물에 대한 혈압이 조절되는 혈압약물반응군과 약물에 대한 혈압이 조절되지 혈압약물비반응군 환자를 동원하여, 트레드밀 운동부하검사를 실시하여 예비심박수를 구하였으며, 이를 근거로 중강도 운동강도(60%HRR)와 고강도 운동강도(85%HRR)의 심박수에서 트레드밀 운동과 고정식자전거 운동을 실시하였다. 혈압의 조절유무에 따라 강도별 트레드밀과 고정식자전거 운동 시에 나타난 심혈관반응의 결과는 다음과 같다. 첫째, 중강도(60%HRR)와 고강도(85%HRR)에서 운동형태(exercise mode)에 따른 혈압약물반응군과 혈압약물비반응군과의 심혈관 반응에 대한 결과 모든 운동강도에서 고정식자전거 운동이 트레드밀 운동보다 수축기혈압, 이완기혈압, 평균동맥혈압, 심근산소소비량, 운동자각도 모두 유의하게 높았다(p<0.05). 또한 고정식 자전거의 60%강도에서 나타난 심혈관계에 미치는 부담이 85%강도의 트레드밀에서 받는 부담과 비슷하였다. 둘째, 혈압약물비반응군은 모든 운동방법(중강도 트레드밀, 고강도 트레드밀, 중강도 고정식자전거, 고강도 고정식자전거)에서 혈압약물반응군보다 유의하게 높은 이완기혈압(DBP)을 나타냈고(p<0.05), 이와 함께 평균동맥혈압(MAP) 역시 모든 운동방법에서 혈압약물비반응군이 혈압약물반응군 보다 유의하게 높았다(p<0.05). 이때, 수축기 혈압에서는 혈압약물비반응군이 중강도자전거 운동방법(60%HRR-cycle exercise)에서만 정상군보다 유의하게 높게 나타났다(p<0.05). 즉, 혈압약물비반응군이 중강도자전거 운동방법에서 수축기혈압과 이완기기혈압, 평균동맥혈압이 혈압약물반응군 보다 유의하게 높았다. 셋째, 심근산소소비량(RPP)에서 혈압약물비반응군과 혈압약물반응군과 중강도자전거 운동에서 유의한 차이는 없었으며 중강도 트레드밀 운동과 중강도자전거 운동 간의 평균 차이에서 중강도자전거 운동이 혈압약물반응군보다 혈압약물비반응군에서 유의하게 높게 증가하였음에도 불구하고 운동자각도(RPE)는 중강도자전거 운동에서 혈압약물반응군과 혈압약물비반응군 간에는 차이를 보이지 않았다. 이상의 결과, 심장재활운동전에 내과적으로 혈압 조절과 상관없이 고혈압 심장질환과 정상혈압 심장질환환자 모두 같은 강도에서 트레드밀보다 고정식 자전거 운동 시에는 모두 철저한 혈압감시가 필요하였다. 특히 고혈압심혈관질환환자는 혈압의 상승폭이 보다 큰 결과를 보여 트레드밀에 적용한 운동 강도를 동일하게 고정식자전거에 적용하는 것은 적합하지 못하였다.

• 한국통신학회논문지
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• 제21권8호
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• pp.2077-2089
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• 1996

In this paper, a memory organization and its control method are proposed for the implementation of parallel Virterbi decoders. The design is mainly focused on lowering the hardware complexity of a parallel Viterbi decoder which is to reduce the decoding speed. The memories requeired in a Viterbi decoder are the SMM(State Metric Memory) and the TBM(Traceback Memory);the SMM for storing the path metrics of states and the TBM for storing the survial path information. A general parallel Viterbi decoder for high datarate usually consists of multiple ACS (Add-Compare-Select) units and their corresponding memeory modules.for parallel ACS units, SMMs and TBMs are partitioned into smaller independent pairs of memory modules which are separately interleaved to provide the maximum processing speed. In this design SMMs are controlled with addrss generators which can simultaneously compute addresses of the new path metrics. A bit shuffle technique is employed to provide a parallel access to the TBMs to store the survivor path informations from multiple ACS modules.