• 한국산학기술학회논문지
• /
• 제12권6호
• /
• pp.2624-2628
• /
• 2011

치과 진료시 파로라마 장치를 이용한 검사에서 유리선량계를 사용하여 피검자의 피폭선량을 측정하였다. 수정체의 피폭선량 영향을 평가하기 위하여 안경의 재질에 따라 수정체의 피폭선량을 측정하였다. 치아위치별 피폭선량 측정결과 $82.4-2,340\;{\mu}Sv$ 선량분포로 나타나 최대 300% 이상의 피폭선량 차이를 보였다. 따라서 효과적이고 정확한 진단과 피폭선량 관리를 위해서는 장치제조 시 예열시간 단축 과 차폐 등의 조치가 필요할 것으로 생각된다. 안경을 착용하였을 때 착용하지 않았을 때 비하여 수정체의 피폭선량이 안경의 재질에 따라서 1회 검사 시 $20-75\;{\mu}Sv$ 증가되는 것으로 측정되었다. 그러므로 피폭선량을 최소화하고 효율적인 검사를 위해 치과 파노라마 검사 시 안경을 벗고 검사할 것을 권고 한다.

• 한국항행학회논문지
• /
• 제15권6호
• /
• pp.1034-1041
• /
• 2011

일반적으로 분산 형 구조의 게임서버시스템 하에서 게임 배경처리는 일정크기로 나누어진 여러 개의 부분 배경들을 다수의 게임서버가 나누어서 처리한다. 그런데 분할된 게임 배경에 대한 게임 사용자들의 선호도가 사용자의 특성에 따라 다르게 나타나기 때문에 모든 게임 배경 내 사용자들의 분포를 일률적으로 만들기는 매우 어렵다. 이 때문에 캐릭터들이 한 장소에 급격히 집중되어 게임이 진행되는 경우, 서버가 처리할 수 있는 한계를 넘어 시스템이 일시적으로 다운되는 문제가 발생 할 수 있으며, 그 반대의 경우 수행할 캐릭터가 없는 상황에서도 배경처리를 계속 수행해야 하므로 게임서버의 효율이 상당히 떨어지게 된다. 이를 해결하기 위하여 본 논문에서는 Map 밸런스 서버를 이용하여 사용자 처리를 위한 부하를 비교적 균등화 시킬 수 있는 Map 관리 방법을 제안 하였다. 제안한 모델 하에서는 사용자가 활동하지 않는 게임 내 공간 처리를 일시 중지시키는 방법으로 게임 서버의 부하를 감소시킬 수 있으며, 서버 간 처리하는 배경을 새로 할당하여 부하를 재분배함으로써 서버들의 효율을 극대화할 수 있다.

• 한국산학기술학회논문지
• /
• 제13권4호
• /
• pp.1923-1930
• /
• 2012

Mn-Cu계 촉매를 사용하여 암모니아 SCR(Selective catalytic Reduction)공정에서 질소산화물 제거능을 측정하였다. 반응온도를 3가지 형태로 변화시키는 조건에서 촉매에 대한 초기반응온도의 영향을 조사하였다. 200, 300 그리고 $340^{\circ}C$에서 소성한 촉매를 사용하여 온도변화에 따른 질소산화물 전환율, 그리고 $H_2$-TPR 시스템에서 온도변화에 따른 수소소모율을 측정하였다. 이산화황가스 공급유무를 조절함으로써 촉매에 대한 이산화황가스의 불활성화 효과를 파악하였다. $340^{\circ}C$ 이상의 온도에서 소성한 촉매는 열적쇼크에 의해 일부 불활성화되며, 이러한 불활성화 원인은 비표면적과 수소 전환율 결과로부터 추론할 수 있다.

• 대한방사선치료학회지
• /
• 제1권1호
• /
• pp.63-69
• /
• 1985

High energy electron beams took effect for tumor radio-therapy, however, had a lot of problems in clinical application because of various conversion factors and complication of physical reactions. Therefore, we had experimentally studied the important properties of high energy electron beams from the linear accelerator, LMR-13, installed in Yonsei Cancer Center. The results of experimental studies on the problems in the 8, 10, 12 Mev electron beam therapy were reported as following. 1. On the measurements of the outputs and absorbed does, the ionization type dosimeters that had calibrated by $^{90}Sr$ standard source were suitable as under $3\%$ errors for high energy electrons to measure, but measuring doses in small field sizes and the regions of rapid fall off dose with ionization chambers were difficult. 2. The electron energy were measured precisely with energy spectrometer consisted of magnet analyzer and tele-control detector and the practical electron energy was calculated under $5\%$ errors by maximum range of high energy electron beam in the water. 3. The correcting factors of perturbated dose distributions owing to radiation field, energy and material of the treatment cone were checked and described systematically and variation of dose distributions due to inhomogeneous tissues and sloping skin surfaces were completely compensated. 4. The electron beams, using the scatters; i.e., gold, tin, copper, lead, aluminium foils, were adequately diffused and minimizing the bremsstrahlung X-ray induced by the electron energy, irradiation field size and material of scatterers, respectively. 5. Inproving of the dose distribution from the methods of pendulum, slit, grid and focusing irradiations, the therapeutic capacity with limited electron energy could be extended.

• 한국재료학회지
• /
• 제23권8호
• /
• pp.453-461
• /
• 2013

Controlling the stick and slip motions of the contact lines in a confined geometry comprised of a spherical lens with a flat substrate is useful for manufacturing polymer ring patterns. We used a sphere on a flat geometry, by which we could control the interfaces of the solution, vapor and substrate. By this method, hundreds of concentric ring-pattern formations of a linear conjugated polymer, poly [2-methoxy-5-(2-thylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), were generated with excellent regularity over large areas after complete solvent evaporation. Subsequently, the MEH-PPV ring patterns played a role as a directed template to organize highly regular concentric rings of single-walled carbon nanotubes(SWCNTs); when a droplet of the SWCNT suspension in water was casted onto the prepared substrate, hydrophobic polymer patterns confined the water dispersed SWCNTs in between the hydrophilicized $SiO_2/Si$ substrate. As the solvent evaporated, SWCNT-rings were formed in between MEH-PPV rings with controlled density. Finally, we used a lift-off process to produce SWCNT patterns by the removal of a sacrificial polymer template with organic solvent. We also fabricated a field effect transistor using self-assembled SWCNT networks on a $SiO_2/Si$ substrate.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권11호
• /
• pp.4503-4508
• /
• 2015

Background: The aims of this study were compare the serum visfatin and resistin levels between endometrial cancer (EC) patients and controls and evaluate their power to predict prognosis. Materials and Methods: This prospective study was conducted between March 2013 to June 2014 on the Gynecologic Oncology Department of the University of Selcuk, Konya, Turkey. A total of 42 EC patients and 42 controls were included and assessed for differences in serum visfatin and resistin levels, along with prognostic factors. Results: Endometrial cancer patients had significantly higher visfatin levels than control s (p: 0.011), associated with deep myometrial invasion (p: 0.019). In contrast the serum level of resistin did not significantly differ between EC patients and controls (p: 0.362). However, high resistin level in EC patients was associated with increase lymph node metastasis (p: 0.009). On logistic regression analysis, we found that serum visfatin elevation was associated with risk of myometrial invasion (OR: 1,091; 95%CI: 1.021-1.166; p: 0.010) and serum resistin with risk of lymph node metastasis (OR: 1.018; 95%CI: 1.000-1.035; p: 0.046). For myometrial invasion prediction, a serum visfatin level greater than 26.8 ng/mL demonstrated a sensitivity and specificity of 66.6 % and 96.4%, respectively. For lymph node metastasis prediction, the best cut-off for serum resistin level was 599ng/mL. A serum resistin level greater than this demonstrated a sensitivity and specificity of 87.5% and 77.1%, respectively. Conclusions: Our data suggest that serum visfatin is elevated in patients with EC and serum visfatin and resistin levels could be used to predict the risk of advance stage lesions.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권1호
• /
• pp.75-80
• /
• 2013

Background: Breast cancer is the most common cancer diagnosed in females in Sri Lanka and early detection can lead to reduction in morbidity and mortality. Aim: To evaluate selected aspects of breast cancer early detection services implemented through well woman clinics (WWCs) in the Gampaha District. Methods: The study consisted of two components. A retrospective descriptive arm assessed clinical breast examination (CBE) coverage of target age group women (TGW) of 35-59 years in all the WWCs in Gampaha district over 2003-2007. A cross sectional descriptive study additionally assessed quality of breast cancer early detection services. The Lot Quality Assurance Sampling (LQAS) technique was used to decide on the lot size and threshold values, which were computed as twenty and six clinics. Checklists were employed in assessing coverage, physical facilities and clinic activities. Client satisfaction on WWC services was assessed among 200 TGW attending 20 WWCs using an interviewer-administered questionnaire. Results: CBE coverage in the Gampaha district increased only from 1.1-2.2% over 2003-2007. With regard to physical facilities, the number of clinics that were rated substandard varied between 7-18 (35-90%). The items that were lacking included dust bins, notice boards, stationary, furniture and linen, and cleanliness of outside premises and toilets. With regard to clinic activities, punctuality of staff, late commencement of clinics, provision of health education, supervision, CBE and breast self-examination (BSE) were substandard in 7-20 clinics (35-100%). Client satisfaction for WWC services was 45.2% (IQR: 38.7-54.8%) and only 11% had a score of ${\geq}70%$, the cut off set for satisfaction. Conclusions: Breast cancer early detection service coverage in the Gampaha district remained low (2.2%) in 2007, 11 years after commencing WWCs. All 20 clinics were substandard for overall CBE and BSE.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제11권4호
• /
• pp.2058-2074
• /
• 2017

Dense Heterogeneous Cellular Networks(HCNs) offer a promising approach to meet the target of 1000x increase in aggregate data rates in 5G wireless communication systems. However how to best utilize the available radio resources at densely deployed small cells remains an open problem as those small cells are typically unplanned. In this paper we focus on balancing loads across macro cells and small cells by offloading users to small cells, as well as dynamically switching off underutilized small cells. We propose a joint user association and base station(BS) sleep mangement(UA-BSM) scheme that proactively offloads users to a fraction of the densely deployed small cells. We propose a heuristic algorithm that iteratively solves the user association problem and puts BSs with low loads into sleep. An interference relation matrix(IRM) is constructed to help us identify the candidate BSs that can be put into sleep. User associations are then aggregated to selected small cells that remain active. Simulation results show that our proposed approach achieves load balancing across macro and small cells and reduces the number of active BSs. Numerical results show user signal to interference ratio(SINR) can be improved by small cell sleep control.

• 한국인터넷방송통신학회논문지
• /
• 제17권4호
• /
• pp.129-135
• /
• 2017

최근 IoT 기술 발전에 따라 스마트 홈과 같은 부가서비스들이 증가하면서 내부에서 사용하는 기기들의 전력 소비량에 대한 관심이 증가하고 있다. 특히 기기들의 주 기능이 수행되지 않는 동안 발생하는 대기전력 사용량이 전력에너지의 약 11%로 나타나면서 대기전력 차단에 대한 문제점이 제시되고 있다. 그러나 실질적으로 대기전력을 차단하기 위해서는 플러그를 뽑아야한다는 문제점이 있다. 따라서 본 논문에서는 이러한 문제점을 개선하기 위해 사용자의 참여도를 최소화하여 자동적으로 제어 및 관리할 수 있는 대기전력 차단 알고리즘을 설계 및 구현하였다. 구현한 시스템을 평가한 결과 기존 시스템보다 평균 약 5.89Wh의 대기전력 차단율이 향상된 것을 확인하였다.

• 대한한방내과학회지
• /
• 제37권6호
• /
• pp.978-989
• /
• 2016

Objectives: This study evaluated the diagnostic values of measuring the number of fungiform papillae in patients with burning mouth syndrome (BMS). Methods: Seventy participants (35 BMS patients and 35 Healthy control) participated in this study. The number of fungiform papillae (FP) was measured on the anterior part of the tongue within an area of $9mm^2$ using a digital camera. The subjects were evaluated on their yin deficiency and blood stasis conditions using the Yin-Deficiency Questionnaire (YDQ) and Blood Stasis Questionnaire (BSQ). Moreover, the severities of subjective tongue pain in the BMS patients were assessed using Visual Analog Scale. Results: There were significant differences in the number of FP and the YDQ and BSQ scores between the two groups. The number of FP and the YDQ scores in the BMS group showed statistically significant correlations with the VAS score of tongue pain. In the bivariate logistic regression analysis, the factor that most strongly contributed to BMS was the number of FP. The optimal cut-off value of the number of fungiform papillae was calculated as 5.5 with 71.4% sensitivity and 82.9% specificity. There was no statistically significant correlation between the number of FP and the YDQ or BSQ score. Conclusions: According to these findings, measuring the number of FP could be a valuable evaluation indicator of BMS.