• 한국의학물리학회지:의학물리
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• 제32권3호
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• pp.59-69
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• 2021

Purpose: The relationship between computed tomography (CT) number and electron density (ED) has been investigated in previous studies. However, the role of these measures for guiding cancer treatment remains unclear. Methods: The CT number was plotted against ED for different imaging protocols. The CT number was imported into ED tables for the Pinnacle treatment planning system (TPS) and was used to determine the effect on dose calculations. Conversion tables for radiation dose calculations were generated and subsequently monitored using a dosimeter to determine the effect of different CT scanning protocols and treatment sites. These tables were used to retrospectively recalculate the radiation therapy plans for 41 patients after an incorrect scanning protocol was inadvertently used. The gamma index was further used to assess the dose distribution, percentage dose difference (DD), and distance-to-agreement (DTA). Results: For densities <1.1 g/cm³, the standard deviation of the CT number was ±0.6% and the greatest variation was noted for brain protocol conditions. For densities >1.1 g/cm³, the standard deviation of the CT number was ±21.2% and the greatest variation occurred for the tube voltage and head and neck (H&N) protocol conditions. These findings suggest that the factors most affecting the CT number are the tube voltage and treatment site (brain and H&N). Gamma index analyses for the 41 retrospective clinical cases, as well as brain metastases and H&N tumors, showed gamma passing rates >90% and <90% for the passing criterion of 2%/2 and 1%/1 mm, respectively. Conclusions: The CT protocol should be carefully decided for TPS. The correct protocol should be used for the corresponding TPS based on the treatment site because this especially affects the dose distribution for brain metastases and H&N tumor recognition. Such steps could help reduce systematic errors.

• 한국의학물리학회지:의학물리
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• 제33권4호
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• pp.142-149
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• 2022

Purpose: This study seeks to compare the dosimetric parameters of the bulk electron density (ED) approach and synthetic computed tomography (CT) image in terms of position variation of the air cavity in magnetic resonance-guided radiotherapy (MRgRT) for patients with pancreatic cancer. Methods: This study included nine patients that previously received MRgRT and their simulation CT and magnetic resonance (MR) images were collected. Air cavities were manually delineated on simulation CT and MR images in the treatment planning system for each patient. The synthetic CT images were generated using the deep learning model trained in a prior study. Two more plans with identical beam parameters were recalculated with ED maps that were either manually overridden by the cavities or derived from the synthetic CT. Dose calculation accuracy was explored in terms of dose-volume histogram parameters and gamma analysis. Results: The D_95% averages were 48.80 Gy, 48.50 Gy, and 48.23 Gy for the original, manually assigned, and synthetic CT-based dose distributions, respectively. The greatest deviation was observed for one patient, whose D_95% to synthetic CT was 1.84 Gy higher than the original plan. Conclusions: The variation of the air cavity position in the gastrointestinal area affects the treatment dose calculation. Synthetic CT-based ED modification would be a significant option for shortening the time-consuming process and improving MRgRT treatment accuracy.

• 한국자기학회지
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• 제26권5호
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• pp.173-178
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• 2016

두경부와 전립선 암 환자에서 CT조영제가 방사선치료계획에 미치는 영향을 확인하고 선량계산 정확성 향상을 위하여 본 연구를 실시하였다. 30명의 환자에 대하여 Pinnacle 8.0 시스템을 이용하여 조영제에 의한 조직의 전자밀도 변화를 측정하였으며 각각의 방사선치료계획을 통한 선량계산을 실시하였다. Pinnacle과 Tomotherapy planning 시스템을 이용하여 각각의 전자밀도와 3D 입체조형방사선치료(3D CRT)와 세기변조방사선치료(IMRT)계획을 수립하였다. 조영제에 의한 전자밀도의 변화는 4%이하로 두경부: 표적용적 2.1%, 이하선 1.9%, 하악선 3.6%, 혀 0.9%, 척수 0.3%, 식도 2.6%, 하악골 0.1%, 전립선: 표적용적 0.7%, 림프절 1.1%, 방광 1.2%, 직장 1.5%, 소장 1.2%, 대장 0.6%, penile bulb 0.8%, 대퇴골두 -0.2%로 나타났다. 선량계산의 차이는 2.5% 이하의 선량 증가가 발생하였다(3D CRT: 두경부 0.69~2.51%, 전립선 0.04~1.14%, IMRT: 두경부 0.58~1.31%, 전립선 0.36~1.04%). 이러한 오차는 임상에서 허용 가능한 오차 이내이지만 영상융합(조영증강 영상과 조영증강 하지않은 영상)이나 ROI import 기능을 활용하여 조영 증강하지 않은 영상에서 선량계산을 실시한다면 1~3%의 방사선치료계획 선량 오차를 줄일 수 있을 것으로 기대된다.

• 한국전기전자재료학회논문지
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• 제28권6호
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• pp.400-402
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• 2015

The typical winter heating unit heating mat. The product is to be found in the development of new water heating mat today. The product that circulates the water through the hose inside the mat with your existing heating mat electric heated mat is different from boiling water. However, no clear standards for noise and safety, consumer choice is giving confusing information about the product is low. We were to develop a high heat retention and stability than conventional sleeping mats to produce creative than traditional hot mats, heated mats general comparison with experimental results is a more efficient heat retention mat is produced.

• 패션정보와 기술
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• 제2권
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• pp.22-32
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• 2005

Sourcing Simulator is specialized form of software capable of providing great insight into merchandising decision making. It is relatively easy to learn and operate by reading the help menus, experimenting with inputs, and critically analyzing outputs. 1 see that it has great potential in a training program for new merchandisers to help them absorb the complexity of the numbers they must effectively use. The Sourcing Simulator, Version 1 that accompanies my textbook, Merchandising: Theory Principles, and Practice, 2nd ed. is the least complex version available. Two versions are available from [TC]2 - Retail version and The Retail/ Manufacturing version. The Retail Version is very similar to the Version 1. The Retail/ Manufacturing Version includes analysis of processes and costs in the manufacturing process as well as the merchandise planning component that we have discussed here. Sourcing Simulator is developed at North Carolina State University by Dr. Russ King, and available from Textile Clothing Technology Corporation $[TC]^2$, Cary, North Carolina.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.151_152
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• 2009

The capacity constraints of tie-lines in production cost analysis are very important issues in the operation and planning of MicroGrid power systems. This paper presents the Harmony Search(HS) algorithm to solve the Economic Dispatch (ED) problem with tie-line capacity limits in MicroGrid system. The applied HS algorithm has achieved efficient and accurate solutions for three-area MicroGrid systems with renewable power units.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.343-344
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• 2006

Consumption of fossil fuel has been increasing steadily, and it has seriously affected environment. Due to this situation, UN establish ed UNFCC (United rations Framework Convention on Climate Change), and since Feb. 2005, Kyoto Protocol has come into effect for UNFCC obligation. In Korean power system, coal and oil thermal generation emitting large CO2 form about 46% of total generation. Moreover since electricity dem and has been increasing continuously, various alternatives should be designed to comply with Kyoto Protocol. In this paper, we analyze changes of each GENCO's generation pattern and resource planning under CO2 emission constraints. For this analysis, we incorporate CO2 emission constraints and the emission trading mechanism into the conventional OPF model.

• 산업경영시스템학회지
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• 제7권10호
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• pp.1-16
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• 1984

The purpose of this paper is to develop rational layout model for small and medium scale industry in Korea. The methodology of this paper is to light the importance of small and medium scale company. Moreover, to overcome the problem of layout in non-massing jobbing production shop this paper is proposed four techniques. So proposed layout model is obtained analytically in single, multiple facility location problem The result of this paper is as follows : First, alternatives to overcome abnormal layout in small and medium company are 1) GT (Group Technology) 2) SLP (Systematic Layout Planning) 3) OR (Operations Research) 4) Computer Second, in single facility location problem, Gradient method and square weighted average method are studied. Lastly in multiple facility location problem, heuristic method is obtained.

• 한국정밀공학회지
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• 제14권3호
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• pp.147-155
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• 1997

Optimal trajectory for a robot manipulator minimizing actuator torques or energy consumptions ina fixed traveling time is obtained in the presence of obstacles. All joint displacements are represented in finite terms of Fourier cosine series and the coefficients of the series are obtained optimally by nonlinear programming. Thus, the geometric path need not be prespecified and the full dynamic model is employed. To avoid the obstacles, the concept of the penalty area is newly introduced and this penalty area is includ- ed in the performance index with an appropriate weighting coefficient. This optimal trajectory will be useful as a geometric path in the minimum-time trajectory planning problem.

• 한국수산과학회지
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• 제42권3호
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• pp.204-208
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• 2009

The withdrawal time of erythromycin in cultured olive flounder was investigated to ensure the food safety of the fish treated with erythromycin. The oral administration of erythromycin was carried out using the experimental diet containing erythromycin (200 mg/kg) daily dose of 40 mg/kg body weight. The 45 day experimental period was broken into 7 days of habituation, 8 days of medication and 30 days of additional feeding without antibiotics. The erythromycin concentration in the flounder muscle had been increased gradually with medication. After 5 days of medication, the concentration increased to its maximum level of 6.05 mg/kg. After discontinuing the antibiotic, the erythromycin concentration decreased drastically and day 9 was below 0.1 mg/kg. The erythromycin concentration had slowly declined from the 6th to the 20th day after medication and disappeared completely after 25 days. From these results, the time needed to reduce the erythromycin level to the 0.2 mg/kg limit adopted by the ED and Japan was suspected to be 4-6 days. Therefore, a reasonable withdrawal time following ED and Japanese regulatory guidelines for erythromycin in the cultured flounder could be estimated to be 10 days.