무인로봇 정밀위치추정을 위한 전술통신 및 영상 기반의 통합항법 성능 분석

최지훈,박용운,송재복,권인소,Choi, Ji-Hoon,Park, Yong-Woon,Song, Jae-Bok,Kweon, In-So 한국군사과학기술학회 2011 한국군사과학기술학회지 Vol.14 No.2

This paper presents a navigation system based on the tactical communication and vision system in outdoor environments which is applied to unmanned robot for perimeter surveillance operations. GPS errors of robot are compensated by the reference station of C2(command and control) vehicle and WiBro(Wireless Broadband) is used for the communication between two systems. In the outdoor environments, GPS signals can be easily blocked due to trees and buildings. In this environments, however, vision system is very efficient because there are many features. With the feature MAP around the operation environments, the robot can estimate the position by the image matching and pose estimation. In the navigation system, thus, operation modes is switched by navigation manager according to some environment conditions. The experimental results show that the unmanned robot can estimate the position very accurately in outdoor environment.

밀폐된 원통형 분무 연소기내의 자연발화 현상에 관한 수치적 연구

최지훈,백승욱,Choi, Ji Hun,Baek, Seung Wook 대한기계학회 1999 大韓機械學會論文集B Vol.23 No.6

In this study, the autoignition process of liquid fuel, injected into hot and stagnant air in a 2-D axisymmetric confined cylindrical combustor, has been investigated. Eulerian-Lagrangian scheme was adopted to analyze the two-phase flow and combustion. The unsteady conservation equations were used to solve the transition of the gas field. Interactions between two phases were accounted by using the particle source in cell (PSI-Cell) model, which was used for detailed consideration of the finite rates of transports between phases. And infinite conduction model was adopted for the vaporization of droplets. The results have shown that the process of the autoignition consists of heating up of droplets, vaporization, mixing and ignition. The ignition criteria could be determined by the temporal variations of temperature, reaction rate and species mass fraction. And the effects of various parameters on ignition phenomena are examined. These have shown that the increasing the reaction rate and/or the vaporization rate can reduce the ignition delay time.

야지환경에서 연합형 필터 기반의 다중센서 융합을 이용한 무인지상로봇 위치추정

최지훈,박용운,주상현,심성대,민지홍,Choi, Ji-Hoon,Park, Yong Woon,Joo, Sang Hyeon,Shim, Seong Dae,Min, Ji Hong 한국군사과학기술학회 2012 한국군사과학기술학회지 Vol.15 No.5

This paper presents UGV localization using multi-sensor fusion based on federated filter in outdoor environments. The conventional GPS/INS integrated system does not guarantee the robustness of localization because GPS is vulnerable to external disturbances. In many environments, however, vision system is very efficient because there are many features compared to the open space and these features can provide much information for UGV localization. Thus, this paper uses the scene matching and pose estimation based vision navigation, magnetic compass and odometer to cope with the GPS-denied environments. NR-mode federated filter is used for system safety. The experiment results with a predefined path demonstrate enhancement of the robustness and accuracy of localization in outdoor environments.

분쇄 계육 가슴살의 도체가공방법과 염지조건이 품질특성에 미치는 영향

최지훈,김일,정종연,이의수,최윤상,김천제,Choi, Ji-Hun,Kim, Il,Jeong, Jong-Youn,Lee, Eui-Soo,Choi, Yun-Sang,Kim, Cheon-Jei 한국축산식품학회 2009 한국축산식품학회지 Vol.29 No.3

This study was carried out to investigate the effect of hot boning and curing condition on the quality characteristics of ground chicken breast. Treatments were cured by four conditions follows; control (general curing method), T1 (after hot-boning and then immediately cured), T2 (after hot-boning and immediately cured, then frozen), and T3 (after hot-boning, immediately frozen, refrigerated and then cured). The pH of chicken breast in the state of pre-rigor was 6.22. The pH of cold storage or freezing chicken breast meat respectively were 5.70 or 5.61. The pH of T1 and T2 treatments were significantly higher than those of control and T3 treatment (p<0.05). After stored for 1 wk, the pH value of T1 treatment had a higher value than those of other treatments. T1 treatment had the highest water holding capacity and the lowest cooking loss among all treatments, regardless of the cooking methods. The reduction in diameter for T1 and T2 treatments was lower than those of control and T3 treatment (p<0.05). T1 treatment had the lowest fat loss and moisture loss among all treatments, and the emulsifying capacity of T1 treatment was the highest. The protein solubility of T1 treatment was significantly lower than that of T3 treatment.

유럽 및 오세아니아의 기능성 축산물과 식육제품에 대한 운영현황 및 관리방안

최지훈,최윤상,김학연,김현욱,김진만,김천제,Choi, Ji-Hun,Choi, Yun-Sang,Kim, Hack-Youn,Kim, Hyun-Wook,Kim, Jin-Man,Kim, Cheon-Jei 한국축산식품학회 2010 한국축산식품학회지 Vol.30 No.5

본 연구는 유럽과 오세아니아의 선진국형 기능성 축산물 및 식육제품의 운영현황 및 관리방안을 연구 분석함으로서 국내 실정에 부합되는 규격기준 표준화와 관리방안 및 제도를 마련하는데 있어서 기초 자료를 제시하는데 있다. 우리나라를 비롯하여 전 세계적으로 국제경쟁력 강화 차원 등의 여러 여건 변화로 식품의 3차적 기능이 점차 강조되고 있다. 따라서 우리나라 자체적으로 기능성 축산물에 대한 정확한 정의와 범위를 확립하는 것이 시급하다. 식품에 기능성 표시를 허용하는 것은 이미 국제적인 대세이다. 유럽과 오세아니아에서도 별도의 기능성 축산물에 관한 법률이나 관리제도가 없으나 식품의 기능성 강화 측면에서 영양표시기준(nutrition claims)과 건강표시기준(health claims)을 통해 식품을 관리하고 있다. 강화 영양소에 대한 표시기준은 일부에 국한되어 있어 이들 기준을 사용하여 국내의 기능성 축산물 및 식육가공품에 적용할 경우, 기능성 지표물질 및 허용량의 설정이 반드시 이루어져야 할 것으로 보이며, EU와 호주 뉴질랜드에서 운영하는 제도 이외의 다른 선진국의 사례를 바탕으로 기능성 축산물에 대한 표준화가 이루어져야 할 것으로 보인다. 또한 기능성 축산물 및 식육제품의 표시를 확립하기 위해서는 현재 시중에 유통되고 있는 제품에 사용되는 기능성 소재 조사 및 각 기능성 소재가 인체에 유해한지 안전성에 대한 연구가 필요하며, 이들 소재의 적정 사용범위 설정을 위한 data base를 확립하기 위해 많은 실험적인 연구가 요구된다. It has recently been considered urgent to establish an accurate definition and scope of functional foods in the livestock industry in Korea. The tertiary function of food is gradually emphasized with various changes in conditions such as international competitive power enhancement of the whole world, including Korea. Therefore, the purpose of this study was carried out to gather basic information toward the establishment of standardization, management plans, and a system adapted to the Korean state through researching management systems of functional meat and meat products in the European Union (EU) and the Oceania Area (OA). A brief summary of this study is as follows. In the EU and OA, special management systems and laws about functional livestock and products were once nonexistent; only 'nutrition claims' and 'health claims' operated in the nutritional consolidation side of foods. Also, it was once thought that functional index materials and permissions established in the application of functional products sufficed, because management standards for enriched food were not established. Therefore, standardization of functional live stock products needs to be considered based on the case of developed countries in the EU and OA. It also seems that the above functional indicative substances can be applied, based on normal standards of indicative substances of functional products and the normal standards of indicators of functional substances added to livestock products presented in this study.

The Effects of Electric Grill and Microwave Oven Reheating Methods on the Quality Characteristics of Precooked Ground Pork Patties with Different NaCl and Phosphate Levels

최지훈,김학연,안광일,김천제,Choi, Ji-Hun,Jeong, Jong-Youn,Kim, Hack-Youn,An, Kwang-Il,Kim, Cheon-Jei Korean Society for Food Science of Animal Resource 2008 한국축산식품학회지 Vol.28 No.5

The objective of this study was to determine the effects of different reheating methods on the quality characteristics of precooked ground pork patties with different combinations of salt (1, 2%) and phosphate (0, 0.3%). The cooking and reheating methods used were the electric grill and the microwave oven. The cooking method and the addition of phosphate had detectable effects on the quality characteristics of ground pork patties. The reheating rate by microwave oven was faster than by electric grill, and decreased with increases in salt and the addition of phosphate. Cooking loss and reduction in patty diameter after reheating by microwave oven were higher than by electric grill, and these values decreased with increasing of salt/phosphate levels. The pH of patties with added phosphate was significantly higher than patties without phosphate, and no significant difference in pH was observed among patties reheated by each method. The patties reheated by electric grill had higher moisture contents than those reheated by electric grill, and the addition of phosphate resulted in higher moisture contents. The hardness of patties reheated by electric grill was lower than patties reheated by microwave oven, and the addition of phosphate increased the hardness with both reheating methods.

The Relationship between Fat Level and Quality Properties of Ground Pork Patties Cooked by Microwave Energy

최지훈,정종연,최윤상,이의수,김천제,Choi, Ji-Hyun,Jeong, Jong-Youn,Choi, Yun-Sang,Lee, Eui-Soo,Kim, Cheon-Jei Korean Society for Food Science of Animal Resource 2008 한국축산식품학회지 Vol.28 No.3

This study was carried out to elucidate the relationship between different fat levels (0%, 5%, 10%, 15%, 20%, and 25%) and the quality of ground pork patties cooked to reach an internal temperature of $75^{\circ}C$ in a microwave oven. The relationship between fat level and cooking rate of pork patties cooked by microwave energy was highly significant ($R^2=0.72$), and had a low determination coefficient ($R^2=0.55$). The relationship between fat level and total cooking loss of pork patties cooked by microwave energy was also very significant, with a high correlation coefficient of $R^2=0.89$. The correlation coefficient between fat level and cooking drip loss of patties cooked by microwave energy was 0.92, which was highly significant. Although the correlation coefficient between fat level and evaporation loss had a negative value ($R^2=-0.63$), there was a highly significant relationship between fat level and shear force of pork patties cooked by microwave energy.

선체-부가물 영향을 고려한 비공동 수중추진기의 소음예측 연구

최지훈,설한신,박일룡,이수갑,Choi, Jihun,Seol, Hanshin,Park, Ilryong,Lee, Soogab 한국음향학회 2019 韓國音響學會誌 Vol.38 No.3

본 연구에서는 대형화, 고속화되어가는 잠수함 추진기의 소음을 보다 정확하게 예측하기 위하여 선체-부가물-추진기의 상호작용이 묘사되는 유동 수치해석을 토대로 비공동 추진기 소음을 예측하였다. 추진기 방사 소음을 예측하기 위해 선체-부가물-추진기 전체영역에 대한 유동 정보를 전산유체역학 해석으로 얻은 뒤, FW-H(Ffowcs Williams-Hawkings) 음향상사법을 적용하여 두께소음, 하중소음에 대한 소음을 수치적으로 예측하였다. 수치적 소음예측 결과는 모형시험을 통해 검증하였으며, 전체 소음 수준과 저주파 대역 소음예측에 있어 계측결과와 좋은 일치를 보였다. In this study, to predict the noise of a submarine propeller which is going to become bigger and faster, the non - cavitating propeller noise was predicted based on the numerical analysis which considering the interaction of the hull - appendages - propeller. In order to predict the radiated noise of the propeller, the flow field for the entire region of hull-appendages-propeller was computed by CFD (Computational Fluid Dynamics). And the noise for the thickness noise and the load noise was numerically predicted using FW-H (Ffwocs Williams-Hawkings) acoustic analogy. Numerical noise prediction results were verified by model tests and showed good agreement with the measurement results in predicting total noise level and low frequency noise.

다중센서 융합기반 소형로봇 자율복귀에 대한 연구

최지훈,강신천,김준,심성대,지태영,송재복,Choi, Ji-Hoon,Kang, Sin-Cheon,Kim, Jun,Shim, Sung-Dae,Jee, Tae-Yong,Song, Jae-Bok 한국군사과학기술학회 2012 한국군사과학기술학회지 Vol.15 No.3

Unmanned ground vehicles may be operated by remote control unit through the wireless communication or autonomously. However, the autonomous technology is still challenging and not perfectly developed. For some reason or other, the wireless communication is not always available. If wireless communication is abruptly disconnected, the UGV will be nothing but a lump of junk. What was worse, the UGV can be captured by enemy. This paper suggests a method, autonomous return technology with which the UGV can autonomously go back to a safer position along the reverse path. The suggested autonomous return technology for UGV is based on multi-correlated information based DB creation and matching. While SUGV moves by remote-control, the multi-correlated information based DB is created with the multi-sensor information; the absolute position of the trajectory is stored in DB if GPS is available and the hybrid MAP based on the fusion of VISION and LADAR is stored with the corresponding relative position if GPS is unavailable. In multi-correlated information based autonomous return, SUGV returns autonomously based on DB; SUGV returns along the trajectory based on GPS-based absolute position if GPS is available. Otherwise, the current position of SUGV is first estimated by the relative position using multi-sensor fusion followed by the matching between the query and DB. Then, the return path is created in MAP and SUGV returns automatically based on the MAP. Experimental results on the pre-built trajectory show the possibility of the successful autonomous return.

지진을 받는 현수교의 수직진동

최지훈,이존자,김수보,이용재,Choi, Jee-Hoon,Lee, Jon-Ja,Kim, Su-Bo,Lee, Yong-Jae 한국강구조학회 2000 韓國鋼構造學會 論文集 Vol.12 No.5

In this study, vertical dynamic analyses on the suspension bridges under seismic load are developed. Time domain analysis, random vibration analysis, and spectral analysis are formulated theoretically. The random nitration analysis is checked by numerical integration and the mathematical integration with correlation coefficient which include CQC and SRSS method in the conditions of white noise and filtered white noise. Beam, truss and frame elements are used in order to model the suspension bridge. Geometric stiffness due to dead load is considered for cable and tower. 본 연구는 지진하중을 받는 현수교의 수직 동적 해석방법을 발전시켰다. 시간 영역해석, 불규칙 진동 해석 및 스펙트럼 해석의 이론을 체계적으로 정립하였다. 불규칙 진동 해석을 다시 수치적분을 이용하는 방법과 수학적 적분식 및 상관계수를 이용한 방법으로 나누고 각각은 다시 지진하중을 white noise로 가정한 경우와 filtered white noise로 가정한 경우에 대해 CQC 방법과 SRSS 방법을 사용하였다. 현수교의 모델링은 빔, 트러스 및 프레임요소를 사용하였고 케이블과 주탑은 사하중에 의한 기하학적 강성을 고려하였다.