• 한국정보과학회논문지:시스템및이론
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• 제32권11_12호
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• pp.682-691
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• 2005

본 논문은 사용자의 제어가 가능한 3차원 물리 기반 가상생명체를 생성하는 2단계 진화 시스템을 제안한다. 기존의 방법은 가상생명체의 형상과 기동, 그리고 목표지점추적(target-following)과 같은 상위 레벨의 행위를 한꺼번에 하나의 진화 시스템으로 생성해냄으로 인하여 진화 단계에서의 사용자의 개입을 허용하지 않았다. 본 논문은 하나로 묶여있던 시스템을 다루기 용이한 두 개의 서브시스템으로 분리함으로써 사용자의 개입을 허용한다. 첫 번째 단계로 가상생명체의 몸체와 직진 기동을 위한 하위 레벨 모터 컨트롤러가 진화 알고리즘(evolutionary algorithm)으로 동시에 생성된다. 두 번째 단계에는 생성된 기본 생명체 위에 주어진 경로를 따라가기 위한 상위 레벨 컨트롤러가 인공 신경망을 사용하여 탑재된다. 경로제어(path-following)를 위한 신경망의 연결 가중치는 유전자 알고리즘(genetic algorithm)을 사용하여 최적화되며 한번 진화된 신경망 컨트롤러는 어떠한 임의의 경로도 잘 따라감을 보여준다. 이로써 사용자는 모든 진화과정이 끝나지 않고도 중간단계에서 기호에 맞는 생명체를 골라내거나 버릴 수 있으며, 동일한 기본 생명체 위에 또 다른 형태의 상위레벨 행위를 생성하는 것도 가능해진다. 본 논문은 이러한 2단계 알고리즘과 함께 직진기동을 위한 새로운 분절 삼각 함수(Piecewise sinusoidal) 컨트롤러를 제안하고 마개 실린더(capped-cylinder)를 기본 요소로 하는 가상생명체에 대한 효율적인 실시간 수중역학 모델링 기법도 함께 소개한다.

• Korean Journal of Radiology
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• 제20권5호
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• pp.830-843
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• 2019

Objective: To examine the potential of intravoxel incoherent motion (IVIM) and blood oxygen level-dependent (BOLD) magnetic resonance imaging for detecting renal changes after iodinated contrast-induced acute kidney injury (CI-AKI) development in a diabetic rabbit model. Materials and Methods: Sixty-two rabbits were randomized into 2 groups: diabetic rabbits with the contrast agent (DCA) and healthy rabbits with the contrast agent (NCA). In each group, 6 rabbits underwent IVIM and BOLD imaging at 1 hour, 1 day, 2 days, 3 days, and 4 days after an iohexol injection while 5 rabbits were selected to undergo blood and histological examinations at these specific time points. Iohexol was administrated at a dose of 2.5 g I/kg of body weight. Further, the apparent transverse relaxation rate (R2^*), average pure molecular diffusion coefficient (D), pseudo-diffusion coefficient (D^*), perfusion fraction (f) were calculated. Results: The D and f values of the renal cortex (CO) and outer medulla (OM) were significantly decreased compared to baseline values in the 2 groups 1 day after the iohexol injection (p < 0.05). A marked reduction in the D^* values for both the CO and OM was also observed after 1 hour in each group (p < 0.05). In the OM, a persistent elevation of the R2^* was detected for 4 days in the DCA group (p < 0.05). Histopathological changes were prominent, and the pathological features of CI-AKI aggravated in the DCA group until day 4. The D, f, and R2^* values significantly correlated with the histological damage scores, hypoxia-inducible transcription factor-1α expression scores, and serum creatinine levels. Conclusion: A combination of IVIM and BOLD imaging may serve as a noninvasive method for detecting and monitoring CI-AKI in the early stages in the diabetic kidney.

• 한국양식학회지
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• 제19권3호
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• pp.210-215
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• 2006

수온과 광주기에 따른 볼락 치어의 대사율 변화를 조사하기 위해 평균 무게 $20.5{\pm}0.7g$을 대상으로 수온(10, 15, 20, $25^{\circ}C$)과 광주기(24L:0D, 12L:12D, 0L:24D)에 따른 산소 소비율은 측정하였다. 12가지 실험 조합의 산소 소비율은 유수식 형태의 호흡실을 이용하여 24시간 동안, 3반복 측정하였다. 수온과 광주기 그리고 두 인자의 상호작용 모두가 볼락 치어의 산소 소비율에 유의한 영향을 미쳤다(P<0.001). 각 광주기 조건에서 수온 상승에 따라 산소 소비율은 유의적으로 증가하였다(P<0.01). 10, 15, 20 그리고 $25^{\circ}C$에서의 시간당 평균 산소 소비율은 각각 $178.3\sim283.5,\;386.7\sim530.7,\;529.2\sim754.3$ 그리고 $590.0\sim785.5mg\;O_2kg^{-1}h^{-1}$였으며, $Q_{10}$ 값은 $10\sim15,\;15\sim20,\;25\sim25^{\circ}C$에서 각각 $3.17\sim5.51,\;1.87\sim2.10,\;1.08\sim1.24$이었다. 연속 명기(24L:0D)에서의 산소 소비율은 연속 암기(0L:24D)에서보다 유의하게 높았다(P<0.05). $10^{\circ}C$를 제외한 모든 수온 조건에서 12L:12D에서 가장 높은 산소 소비율을 보였으며, 24L:0D의 명기에서의 산소 소비율은 같은 조건의 암기 때보다 유의하게 높은 산소 소비율을 보였다(P<0.05). 이 실험 결과는 각 수온과 광주기 조건에서의 볼락 치어의 산소 소비율을 파악할 수 있으며, 사육관리 및 생리적 반응 정량화를 위한 생체역학 모델 결정에 활용할 수 있다.

• Asian-Australasian Journal of Animal Sciences
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• 제33권10호
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• pp.1624-1632
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• 2020

Objective: A total of three hundred unsexed ducks were utilized to estimate net energy requirements of maintenance (NE_m) and weight gain (NE_g) for 2 to 3-week-old Cherry Valley ducks and to establish a model equation to predict NE requirements using the factorial method. Methods: To determine the apparent metabolizable energy (AME) of the diet, fifty 7-day-old ducks at approximately equal body weights (BWs) were randomly assigned into five groups that were fed at different levels (ad libitum, 85%, 75%, 65%, and 55% of ad libitum intake), and the endogenous acid-insoluble ash as indigestible marker. The two hundred and fifty 7-day-old ducks were used for a comparative slaughter experiment. At the beginning of the experiment, ten ducks were sacrificed to determine the initial body composition and energy content. The remaining ducks were randomly assigned into five groups (same as metabolic experiment). Ducks of the ad libitum group were slaughtered at 14 and 21-day-old. At the end of the experiment, two ducks were selected from each replicate and slaughtered to determine the body composition and energy content. Results: The results of the metabolizable experiment showed AME values of 13.43 to 13.77 MJ/kg for ducks at different feed intakes. The results of the comparative slaughter experiment showed the NE_m value for 2 to 3-week-old Cherry Valley ducks was 549.54 kJ/kg of BW^0.75/d, and the NE_g value was 10.41 kJ/g. The deposition efficiency values of fat (K_f) and crude protein (K_p) were 0.96 and 0.60, respectively, and the values of efficiency of energy utilization (K_g) and maintenance efficiency (K_m) were 0.75 and 0.88, respectively. Conclusion: The equation for the prediction of NE requirements for 2 to 3-week-old Cherry Valley ducks was the following: NE = 549.54 BW^0.75+10.41 ΔW, where ΔW is the weight gain (g).

• 한국의학물리학회지:의학물리
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• 제10권3호
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• pp.133-140
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• 1999

본 연구에서는 외부조사 전자선에 대한 3 차원 선량계산 알고리즘 모델을 개발하기 위한 기초연구로서 기존의 2D 펜실빔 알고리즘을 확장시켜 3 차원 geometry를 적절히 고려할 수 있는 선량계산 모델을 개발하고자 한다. 선량계산 모듈은 IDL5.2(Reseach Systems Inc. 미국)를 사용하여 프로그램하였으며, Hogstrom의 펜실빔 모델에 의한 선량계산에 필요한 중심축 상의 깊이선량분포는 Siemens M6740의 12MeV 전자선에 대한 측정치를 사용하였고, 전자선의 공기 및 불에서의 선형저지능 (linear stopping power), 선형산란능 (linear scattering power) 은 ICRU 보고서 35로부터 인용하여 사용하였다. 선량계산의 정확도를 확인하기 위하여 정형 조사면에 대한 선량분포 공기 간격 효과 인체 외곽 보정에 대해 전리함, 필름 등을 사용하여 얻은 측정값과 비교, 분석하였다. PC(Pentium III 450MHz) 상에서 프로그램 실행 결과 단일 조사 빔에 대한 선량계산에 약 120초가 소요되어, 선량계산 알고리즘의 최적화를 통한 선량계산 시간 단축이 필요하다 하겠다. 선량 평가에 대한 비교 결과, 정형 및 비정형 조사변에 대한 선량분포는 선량변화가 급격한 반음영 (penumbra) 영역에서 $\pm$3mm 이내의 오차를 보였으며, 측방 선량분포에 따른 비교 결과, 측정치와 5% 이내에서 일치하였다. 또한 공기 간격 및 인체 외곽선 보정의 경우, $\pm$10% 내외에서 측정값과 일치하였다. 결론적으로, 전자선에 대한 2 차원 펜실빔 모델을 확장하여 3 차원 치료계획에 적합하게 3 차원상의 임의의 단변 선량계산이 가능하도록 구현되었다. 또한 비정형 조사변에 대한 선량계산 뿐만 아니라, 인체외곽 및 공기 간격 등과 같이 3 차원적 geometry에 대한 보정이 필요한 경우에 대하여도 이를 선량계산 시 적절히 고려함을 확인할 수 있었다. 추후, CT를 통한 비균질 보정방식을 구현할 계획이며, 이들 선량계산 모듈은 교육 및 연구용으로 적절히 활용할 수 있을 것으로 기대된다.

• Journal of Magnetics
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• 제19권2호
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• pp.185-191
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• 2014

In this study we evaluated that flow rate changes affect the (time of flight) TOF image and contrast-enhanced (CE) in a three-dimensional TOF angiography. We used a 3.0T MR System, a nonpulsatile flow rate model. Saline was used as a fluid injected at a flow rate of 11.4 cm/sec by auto injector. The fluid signal strength, phantom body signal strength and background signal strength were measured at 1, 5, 10, 15, 20 and 25-th cross-section in the experienced images and then they were used to determine signal-to-noise ratio and contrast-to-noise ratio. The inlet, middle and outlet length were measured using coronal images obtained through the maximum intensity projection method. As a result, the length of inner cavity was 2.66 mm with no difference among the inlet, middle and outlet length. We also could know that the magnification rate is 49-55.6% in inlet part, 49-59% in middle part and 49-59% in outlet part, and so the image is generally larger than in the actual measurement. Signal-to-noise ratio and contrast-to-noise ratio were negatively correlated with the fluid velocity and so we could see that signal-to-noise ratio and contrast-to-noise ratio are reduced by faster fluid velocity. Signal-to-noise ratio was 42.2-52.5 in 5-25th section and contrast-to-noise ratio was from 34.0-46.1 also not different, but there was a difference in the 1st section. The smallest 3D TOF MRA measure was $2.51{\pm}0.12mm$ with a flow velocity of 40 cm/s. Consequently, 3D TOF MRA tests show that the faster fluid velocity decreases the signal-to-noise ratio and contrast-to-noise ratio, and basically it can be determined that 3D TOF MRA and 3D CE MRA are displayed larger than in the actual measurement.

• 한국축산식품학회지
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• 제34권1호
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• pp.49-56
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• 2014

The present study was carried out to investigate the effects of nanopowdered peanut sprout-added Caciocavallo cheese (NPCC) on the prevention and treatment of rheumatoid arthritis in DBA/IJ mice immunized with type II collagen. After the induction of arthritis, the mice were being divided into five groups: (1) normal, no immunization; (2) CIA, collagen-induced arthritis; (3) MTX, collagen-induced arthritis treated with methotrexate (0.3 mg/kg body weight); (4) CC, collagen-induced arthritis treated with Caciocavallo cheese (0.6 g/d); (5) NPCC, collagen-induced arthritis treated with nanopowdered peanut sprout-added Caciocavallo cheese (0.6 g/d). Nanopowdered peanut sprout was ranged from 300 to 350 nm, while regular powdered peanut sprouts were ranged from 50 to $150{\mu}m$. The NPCC group had considerable reductions of clinical scores and paw thicknesses at the end of experiment as compared to the CIA group. In the serum analysis, the TNF-${\alpha}$, IL-$1{\beta}$, IL-6 and $IgG_1$ levels in the NPCC group have decreased by 69.4, 75.9, 66.6, and 61.9%, respectively, when compared to the CIA group. The histological score and spleen index of the NPCC group were significantly lower than the CIA group. In conclusion, the feeding NPCC method could delay and/or prevent the rheumatoid arthritis in the collagen-induced arthritis mouse model. Based on this study, nanopowdered peanut sprouts could be applied to various functional cheeses.

• Journal of Microbiology and Biotechnology
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• 제32권2호
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• pp.228-237
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• 2022

In this study, the effects of the immune stimulator Euglena gracilis (Euglena) in cyclophosphamide (CCP)-induced immunocompromised mice were assessed. The key component β-1,3-glucan (paramylon) constitutes 50% of E. gracilis. Mice were orally administered Euglena powder (250 and 500 mg/kg body weight (B.W.)) or β-glucan powder (250 mg/kg B.W.) for 19 days. In a preliminary immunology experiment, ICR mice were intraperitoneally injected with 80 mg of CCP/kg B.W. during the final 3 consecutive days. In the main experiment, BALB/c mice were treated with CCP for the final 5 days. To evaluate the enhancing effects of Euglena on the immune system, mouse B.W., the spleen index, natural killer (NK) cell activity and mRNA expression in splenocytes lungs and livers were determined. To detect cytokine and receptor expression, splenocytes were treated with 5 ㎍/ml concanavalin A or 1 ㎍/ml lipopolysaccharide. The B.W. and spleen index were significantly increased and NK cell activity was slightly enhanced in all the experimental groups compared to the CCP-only group. In splenocytes, the gene expression levels of tumor necrosis factor-α, interferon-γ, interleukin (IL)-10, IL-6, and IL-12 receptor were increased in the E. gracilis and β-glucan groups compared to the CCP-only group, but there was no significant difference. Treatment with 500 mg of Euglena/kg B.W. significantly upregulated dectin-1 mRNA expression in the lung and liver compared to the CCP-only group. These results suggest that Euglena may enhance the immune system by strengthening innate immunity through immunosuppression.

• Journal of Biosystems Engineering
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• 제30권6호통권113호
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• pp.366-372
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• 2005

The objective of this study was to evaluate the bump crossing and loading stability of a proto-type mini-forwarder under development. The evaluation was performed by computer simulation using a multi-body dynamic analysis program, Recur- Dyn 5.21. The proto-type was modeled and its properties such as mass, mass center, and mass moment of inertia were determined using 3D CAD modeler, Solid Edge 8.0. The $\%$ errors of masses, mass center, mass moment of inertia, and vertical motion of the model were within less than $10\%$ and the model's behavior agreed relatively well with those of the proto-type when traversing over a rectangular bump. Using the validated model, bump crossing of the proto-type was simulated and the loading limit was determined. It was found that effects of the shapes of bump on the bump crossing performance was insignificant within the practical heights of bumps. Stability of bump crossing increased with loading. However, loading of longer logs than 2.7 m made the crossing unstable because the ends of logs contacted ground when traversing over the bump. The maximum loading capacity of the proto-type was estimated to be 7.8 kN of 2.7 m long logs.

• 대한의용생체공학회:의공학회지
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• 제30권3호
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• pp.221-225
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• 2009

The purpose of this study was to investigate the biomechanical effects of an application of whole body vibration during strengthening exercise. Every participant performed four weeks exercise program using general leg-press versus vibrating leg-press. Participants did legpress exercise three sets of 25 repetitions with the load of 25 percent of 1RM during first week, three sets of 20 repetitions with 40 percent of 1RM during second week, three sets of 15 repetitions with 60 percents of 1RM during third week, and three sets of 15 repetitions with 80 percent of 1RM during last fourth week. The vibration(25Hz, 5mm) was applied only to the vibration exercise group. A three dimensional virtual lower extremity model for one of subject and virtual leg-press model were generated. The knee extensor muscle forces were analyzed using the virtual model and the knee joint torque(maximum extension torque) was measured using an isokinetic device. Calculated muscle forces were smaller in vibrating leg-press exercise than in general leg-press exercise. An increase of the maximum knee extension joint torque was 2.14 times larger approximately after the four week vibration leg-press exercise program was performed.