• 대한의용생체공학회:의공학회지
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• 제29권1호
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• pp.40-45
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• 2008

Therapeutic ultrasound which is developed for rehabilitation therapy have already been used for healing joint contracture, synechia, acute and chronic inflammatory diseases. Medical devices for pain-relief and healing using therapeutic ultrasound are actively being developed. This study measured the change of PTT with the transmitted ultrasound through the human body to find out the increase of compliance of blood vessels. Measurement method of PTT in this study is employed as useful ways to acquire physiological information of patients in the clinical case in order to measure the change of mechanical characteristics of blood vessels. This study confirmed the PTT change of rehabilitation patients through the thermal effects of ultrasound by using PTT and also found that it is possible to increase PTT by adjusting the warm water and ultrasound. The increase of PTT means the decrease of the pulse wave velocity from the cardiovascular system to the peripheral arteries. The physiological effects occurred using the warm water and ultrasound.

• 한국정보과학회논문지:소프트웨어및응용
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• 제29권1_2호
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• pp.1-9
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• 2002

진화 신경망은 기존의 경험적 지식 대신에 진화 알고리즘의 전역 탐색 능력을 사용해서 최적의 신경망을 찾는다. 하지만 실세계의 복잡한 문제는 하나의 신경망으로 해결하기 어려운 경우가 많기 때문에 최근에 하나 이상의 신경망을 결합한 다중 신경망에 관한 연구가 활발히 진행되고 있다. 본 논문에서는 진화과정 중 상호보완 가능한 다양한 신경망을 얻기 위한 종분화 방식을 제안한다. 또한 적합도 공유를 통해 종분화된 진화 신경망의 결과를 효과적으로 결합하기 위해 추상 레벨, 순위 레벨, 측정치 레벨의 여러 결합 방법을 이용한 다중 신경망 시스템을 개발한다. UCI 데이터베이스의 벤치마크 문제 중 호주 신용카드 승인 데이터에 대하여 실험한 결과, 종분화를 사용해 탐색한 신경망을 결합한 경우는 더 높은 인식률을 보였으며 Borda 결합의 경우 0.105의 오류율을 보여 제안한 방법이 효과적임을 알 수 있었다.

• 한국식품조리과학회지
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• 제19권3호
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• pp.308-317
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• 2003

The purpose of this study was to identify combinations of factors, with regard to the use of restaurants by tourists, and to establish the relative importance of these factors in terms of their contribution to the total usage. Of 250 questionnaires, 209 were utilized for analysis in this study. Crosstabs, conjoint analysis, paired-samples t-test, k-means cluster analysis, one-way ANOVA analysis, and the Friedman test were used for the statistical analysis. The findings from this study were as follows: First, the Pearson's R and Kendall's tau statistics show that the model fits the data well. Second, it was found that 209 tourists most preferred restaurants that provided excellent quality traditional food, with a high quality of service, at a cheap price for the suburb. The 81 tourists of the first cluster most preferred restaurant that provided excellent quality fusion food, at a cheap price for the suburb. The 65 tourists of tile second cluster most preferred restaurant that provided average quality national food, at an expensive price for the suburb. The 63 tourists of the third cluster most preferred restaurant that provided excellent quality traditional food, at a reasonable price for the suburb. Third, it wis found that all tourists and the three clusters groups regarded both the type of food and its price to be very important factors. Finally, the results used in this study have provided some insight into the types of marketing strategies and tourism policies that may be successfully used by the operators and policymakers managing a location, the quality, price and type of food, and quality of service required by tourists dining at restaurants.

• 드라이브 ㆍ 컨트롤
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• 제16권3호
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• pp.51-58
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• 2019

The objective of this study was to investigate a simulation technology for the AM field based on ANSYS Inc.. The introduction of metal 3D printing AM process, and the examining of the present status of AM process simulation software, and the AM process simulation processor were done in the previous study (part 1). This present study (part 2) examined the use of the AM process simulation processor, presented in Part 1, through direct execution of Topology Optimization, Ansys Workbench, Additive Print and Additive Science. Topology Optimization can optimize additive geometry to reduce mass while maintaining strength for AM products. This can reduce the amount of material required for additive and significantly reduce additive build time. Ansys Workbench and Additive Print simulate the build process in the AM process and optimize various process variables (printing parameters and supporter composition), which will enable the AM to predict the problems that may occur during the build process, and can also be used to predict and correct deformations in geometry. Additive Science can simulate the material to find the material characteristic before the AM process simulation or build-up. This can be done by combining specimen preparation, measurement, and simulation for material measurements to find the exact material characteristics. This study will enable the understanding of the general process of AM simulation more easily. Furthermore, it will be of great help to a reader who wants to experience and appreciate AM simulation for the first time.

• 대한방사선기술학회지:방사선기술과학
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• 제41권6호
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• pp.553-560
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• 2018

PET-CT and PET-MRI which integrates CT using ionized radiation and MRI using phenomena of magnetic resonance are determined to have the limitation to apply the semi-quantitative index, standardized uptake value (SUV), with the same level due to the fundamental differences of image capturing principle and reorganization, hence, their correlations were analyzed to provide their clinical information. To 30 study subjects maintaining pre-treatment, $^{18}F-FDG$ (5.18 MBq/㎏) was injected and they were scanned continuously without delaying time using $Biograph^{TM}$ mMR 3T (Siemens, Munich) and Biograph mCT 64 (Siemens, Germany), which is an integral type, under the optimized condition except the structural differences of both scanners. Upon the measurement results of $SUV_{max}$ setting volume region of interest with evenly distributed radioactive pharmaceuticals by captured images, $SUV_{max}$ mean values of PET-CT and PET-MRI were $2.94{\pm}0.55$ and $2.45{\pm}0.52$, respectively, and the value of PET-MRI was measured lower by $-20.85{\pm}7.26%$ than that of PET-CT. Also, there was a statistically significant difference in SUVs between two scanners (P<0.001), hence, SUV of PET-CT and PET-MRI cannot express the clinical meanings in the same level. Therefore, in case of the patients who undergo cross follow-up tests with PET-CT and PET-MRI, diagnostic information should be analyzed considering the conditions of SUV differences in both scanners.

• Journal of Korean Neurosurgical Society
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• 제62권1호
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• pp.61-70
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• 2019

Objective : Corpectomy of the first lumbar vertebra (L1) for the management of different L1 pathologies can be performed using either an anterior or posterior approach. The aim of this study was to evaluate the usefulness of a retroperitoneal extrapleural approach through the twelfth rib for performing L1 corpectomy. Methods : Thirty consecutive patients underwent L1 corpectomy between 2010 and 2016. The retroperitoneal extrapleural approach through the 12th rib was used in all cases to perform single-stage anterior L1 corpectomy, reconstruction and anterior instrumentation, except for in two recurrent cases in which posterior fixation was added. Visual analogue scale (VAS) was used for pain intensity measurement and ASIA impairment scale for neurological assessment. The mean follow-up period was 14.5 months. Results : The sample included 18 males and 12 females, and the mean age was 40.3 years. Twenty patients (67%) had sensory or motor deficits before the surgery. The pathologies encountered included traumatic fracture in 12 cases, osteoporotic fracture in four cases, tumor in eight cases and spinal infection in the remaining six cases. The surgeries were performed from the left side, except in two cases. There was significant improvement of back pain and radicular pain as recorded by VAS. One patient exhibited postoperative neurological deterioration due to bone graft dislodgement. All patients with deficits at least partially improved after the surgery. During the follow-up, no hardware failures or losses of correction were detected. Conclusion : The retroperitoneal extrapleural approach through the 12th rib is a feasible approach for L1 corpectomy that can combine adequate decompression of the dural sac with effective biomechanical restoration of the compromised anterior loadbearing column. It is associated with less pulmonary complication, no need for chest tube, no abdominal distention and rapid recovery compared with other approaches.

• 정보보호학회논문지
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• 제17권6호
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• pp.19-28
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• 2007

본 논문은 지문 데이터베이스를 평가하는데 가장 큰 영향을 미치는 image quality를 측정하는 새로운 방법을 제안한다. 본 논문에서는 image quality를 측정하는 hybrid segmentation 방법을 소개하고, 다양한 지문 데이터베이스에 대해 실험한 결과를 분석한다. 개발한 방법의 객관적인 평가를 위해 NIST에서 제공하는 NFIQ 프로그램을 통해 얻은 결과와 variance와 coherence의 fusion을 이용한 hybrid segmentation 결과를 비교한다. NFIQ는 지문 영상의 품질을 정확하게 측정하지만 결과가 $1{\sim}5$로 세분화되어 있지 못한 문제점을 가지고 있다. 반면 제안하는 hybrid 방법은 NFIQ보다 더 정확하고 세분화된 평가 결과를 제공한다. 두 방법에 의해 실험한 데이터베이스들을 평가한 결과, 동일한 영상에 대해 NFIQ와 hybrid segmentation의 결과가 유사하며 지문 영상의 품질을 세분화하여 측정할 수 있는 점에서 NFIQ보다 뛰어나다고 할 수 있다.

• 한국정보통신학회논문지
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• 제25권8호
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• pp.1046-1052
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• 2021

4차 산업의 발전과 고성능의 컴퓨팅 환경 구축으로 다양한 산업분야에서 인공지능이 적용되고 있다. 의료분야에서는 X-Ray, MRI, PET 등의 의료 영상 및 임상 자료를 이용하여 암, COVID-19, 골 연령 측정 등의 딥 러닝 학습이 진행되었다. 또한 스마트 의료기기, IoT 디바이스와 딥 러닝 알고리즘을 적용하여 ICT 의료 융합 기술 등이 연구되고 있다. 이러한 기술 중 의료 영상 기반 딥 러닝 학습은 의료 영상의 바이오마커를 정확히 찾아내고, 최소한의 손실률과 높은 정확도가 필요하다. 따라서 본 논문은 흉부 X-Ray 이미지 기반 딥 러닝 학습 과정에서 손실률을 도출하는 손실 함수 중 영상분류 알고리즘에서 사용되는 Cross-Entropy 함수들의 성능을 비교·분석하고자 한다.

• 한국융합학회논문지
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• 제13권4호
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• pp.137-145
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• 2022

비대면 의료시스템의 확대로 간호사의 업무 경감 및 효율성을 높이기 위해서 도입되는 원격수액모니터링 장치의 사용성평가를 수행하였다. 원격 수액 모니터링은 수액 측정시술과 분석, 오차 교정기술, 전송기술 등 다양한 기술이 융복합되어 있다. 사용자가 사용하는 범위와 얻고자 하는 정보, 조절 장치 등 사용범위가 넓으며 제품을 평가하는 요소도 다양하다. 따라서 평가를 통해 제품을 개선하는데 어려움이 있다. 본 연구에서는 원격수액모니터링 시스템장치를 제품의 안정성, 조작성, 만족도의 3개 영역에서 20개의 사용성평가를 실시하여 상용화를 위한 제품개선에 도움을 주고자 정량적인 지표를 개발하였다. 적외선 방식과 로드셀 방식의 수액모니터링 장치를 통해 수행하였으며, 안정성에서는 장치의 폴대고정 등 설치작업에 대해 차이가 있었으며, 조작성과 정확성에 대해서는 높은 만족도를 나타내었다. 제품의 만족도에서는 로드셀 장치의 만족도가 대체로 높게 나타났다.

• Nuclear Engineering and Technology
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• 제55권3호
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• pp.919-926
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• 2023

To analyze the cause of the destruction of thin, carbon-backed lithium fluoride targets during a measurement of the fusion of ⁷Li and ¹⁷O, we estimate theoretically the lifetimes of carbon and LiF films due to sputtering, thermal evaporation, and lattice damage and compare them with the lifetime observed in the experiment. Sputtering yields and thermal evaporation rates in carbon and LiF films are too low to play significant roles in the destruction of the targets. We estimate the lifetime of the target due to lattice damage of the carbon backing and the LiF film using a previously reported model. In the experiment, elastically scattered target and beam ions were detected by surface silicon barrier (SSB) detectors so that the product of the beam flux and the target density could be monitored during the experiment. The areas of the targets exposed to different beam intensities and fluences were degraded and then perforated, forming holes with a diameter around the beam spot size. Overall, the target thickness tends to decrease linearly as a function of the beam fluence. However, the thickness also exhibits an increasing interval after SSB counts per beam ion decreases linearly, extending the target lifetime. The lifetime of thin LiF film as determined by lattice damage is calculated for the first time using a lattice damage model, and the calculated lifetime agrees well with the observed target lifetime during the experiment. In experiments using a thin LiF target to induce nuclear reactions, this study suggests methods to predict the lifetime of the LiF film and arrange the experimental plan for maximum efficiency.