• Journal of Photoscience
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• v.9 no.2
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• pp.243-245
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• 2002

Pigment-dispersing factor (PDF) is an octadecapeptide distributed in the optic lobe and the brain in a variety of insect species. There are lines of evidence suggesting possible involvement of PDF in the insect circadian system. However, its physiological roles in the circadian time keeping mechanism have not been clearly defined. In this study, we have examined the phase shifting effects of Gryllus-PDF on the circadian locomotor rhythm in the cricket Gryllus bimaculatus of which circadian clock is located in the optic lobe. Phase shifts in the circadian activity rhythm were measured following microinjection of 22nl of vehicle (Ringer's solution) or O.lmM PDF into the optic lobe through the compound eye at various circadian times. The results showed that PDF induced phase shifts of the circadian clock in a phase-dependent manner, suggesting that it may play a role as an input signal for the circadian clock.

• Proceedings of the Korean Society of Computer Information Conference
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• 2016.07a
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• pp.3-4
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• 2016

멀티스레드 프로그램의 수행 중에 발생할 수 있는 자료경합은 프로그래머가 의도하지 않은 비결정적 수행으로 인해 신뢰할 수 없는 프로그램의 결과를 발생시킨다. 이러한 자료경합의 디버깅을 위해서 시간 및 자원적 비용이 과도하게 발생하기 때문에 프로그램의 수행 중에 이를 용인하고 치유하는 것이 중요하다. 본 논문은 멀티스레드 프로그램을 대상으로 소프트웨어 트랜잭셔널 메모리(STM)를 사용하여 공유변수에 대한 트랜잭션 영역을 설정하고 공유변수에 대한 이벤트 충돌 유형에 따른 자료경합 치유기법을 설계한다. 최종적으로는 프로그램 수행 중에 자료경합을 치유하는 기법의 실현가능성을 확인한다.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.8
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• pp.702-708
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• 2013

Underwater TRN (Underwater Terrain Referenced Navigation) estimates an underwater vehicle state by measuring a distance between the vehicle and undersea terrain, and comparing it with the known terrain database. TRN belongs to absolute navigation methods, which are used to compensate a drift error of dead reckoning measurements such as IMU (Inertial Measurement Unit) or DVL (Doppler Velocity Log). However, underwater TRN is different to other absolute methods such as USBL (Ultra-Short Baseline) and LBL (Long Baseline), because TRN is independent of the external environment. As a magnetic-field-based navigation, TRN is a kind of geophysical navigation. This paper develops an EKF (Extended Kalman Filter) formulation for underwater TRN. A filter propagation part is composed by an inertial navigation system, and a filter update is executed with echo-sounder measurement. For large-initial-error cases, an adaptive EKF approach is also presented, to keep the filter be stable. At the end, simulation studies are given to verify the performance of the proposed TRN filter. With simplified sensor and terrain database models, the simulation results show that the underwater TRN could support conventional underwater navigation methods.

• Journal of Digital Convergence
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• v.12 no.9
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• pp.177-192
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• 2014

Telematics is a compound word derived from telecommunication and informatics, which provides wireless data service such as traffic information, living information, remote control, maintenance and etc. in a vehicle using GPS(Global Positioning System) and telecommunication. Telematics acceptance was investigated to analyze characteristics of telematics service and its market by using a theoretical technology acceptance model based on literature review. In this paper, valid factors, influencing telematics service acceptance, have been drawn in terms of user ease-of-use, usefulness and service characteristics. Modified measuring variables were used by referring to previous researches.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.4
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• pp.426-434
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• 2021

In this paper, three-dimensional unsteady computational fluid dynamic(CFD) analyses based on overset grid technique have been performed for a hand-launched unmanned aerial vehicle(UAV) considering the wake effect generated by a rotating propeller. In addition, the defection of rudder is considered in order to consider to predict the equilibrium condition of yawing moment during cruise flight conditions. It is importantly shown in this paper that the wake interference effect of the propeller is significant to accurately predict the yawing moment of the UAV and the yawing moment coefficient corresponding to a flight speed can be different because of its different amount of wake effect due to the different rotating speed of the propeller.

• International Journal of Aerospace System Engineering
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• v.2 no.2
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• pp.29-33
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• 2015

The multidisciplinary design optimization (MDO) of a launch vehicle (LV) with a hybrid rocket engine (HRE) was carried out to investigate the ability of an HRE for a single-stage LV. The non-dominated sorting genetic algorithm-II (NSGA-II) was employed to solve two design problems. The design problems were formulated as two-objective cases involving maximization of the downrange distance over the target flight altitude and minimization of the gross weight, for two target altitudes: 50.0 km and 100.0 km. Each objective function was empirically estimated. Several non-dominated solutions were obtained using the NSGA-II for each design problem, and in each case, a trade-off was observed between the two objective functions. The results for the two design problem indicate that economical performance of the LV is limited with the HRE in terms of the maximum downrange distances achievable. The LV geometries determined from the non-dominated solutions were examined.

• Journal of Intelligence and Information Systems
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• v.28 no.2
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• pp.57-74
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• 2022

Recently, artificial intelligence parking control systems have increased the recognition rate of vehicle license plates using deep learning, but there is a problem that they cannot determine vehicles with fake license plates. Despite these security problems, several institutions have been using the existing system so far. For example, in an experiment using a counterfeit license plate, there are cases of successful entry into major government agencies. This paper proposes an improved system over the existing artificial intelligence parking control system to prevent vehicles with such fake license plates from entering. The proposed method is to use the degree of matching of the front feature points of the vehicle as a passing criterion using the ORB algorithm that extracts information on feature points characterized by an image, just as the existing system uses the matching of vehicle license plates as a passing criterion. In addition, a procedure for checking whether a vehicle exists inside was included in the proposed system to prevent the entry of the same type of vehicle with a fake license plate. As a result of the experiment, it showed the improved performance in identifying vehicles with fake license plates compared to the existing system. These results confirmed that the methods proposed in this paper could be applied to the existing parking control system while taking the flow of the original artificial intelligence parking control system to prevent vehicles with fake license plates from entering.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.178-180
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• 2022

최근 차량 플랫폼의 발달로 인하여 차량 내 ECU 간의 정보교환이 증가하였다. 기존의 센트럴 게이트웨이 아키텍처 네트워크에서는 늘어난 정보교환으로 인한 과부하가 발생하였다. 따라서 ECU 들끼리 Domain 을 형성하도록 하여 DCU 를 활용한 Domain 기반 차량용 통신 아키텍처가 해법으로 제시되었다. 본 연구에서는 DCU 와 ECU 간의 네트워크 플랫폼을 소형 전동차를 이용하여 제작한다. 이 네트워크를 검증하기 위하여 목표물 추적 알고리즘을 통해 네트워크가 정상 작동하는지 확인한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2022.06a
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• pp.330-331
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• 2022

자율주행 차량의 운전자는 현재 레벨3에서 탑승하는 운전자에부터 최종적으로 레벨 5단계에서 탑승자로 변화하게 된다. 관련하여 자율주행차량이 운행하는 동안 탑승자는 무엇을 하는지가 중요한 이슈로 대두될 여지가 있다. 탑승자는 뉴스를 읽거나 노래를 부르거나 주변 환경을 감상할 수 있고, 또는 탑승자는 다른 탑승자와 게임을 하거나 대화를 하거나 회의와 의사결정을 내릴 수도 있다. 자율주행차량은 이용자의 활용에 따라 오락공간, 휴식공간, 회의공간으로 트랜스포메이션되는 셈이다. 본 논문은 자율주행차량에서 블록체인 기술 중 하나인 NFT를 활용하여 차량의 탑승자에게 소유권이 있는 생산 데이터에 대해 스마트 계약을 구현하는 방법에 대하여 연구하였다. 자율주행 차량 내에서의 소유권을 표식한 스마트 계약 체결과 향후 적용 운용환경을 연구.개발하였다.

• Journal of Aerospace System Engineering
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• v.16 no.6
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• pp.114-122
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• 2022

This paper explores three-dimensional unsteady computational fluid dynamic (CFD) analyses with an overset grid technique to analyse the wake effect created by a rotating propeller on a hand-launched unmanned aerial vehicle (UAV). Additionally, the influence of actual aileron deflection on the equilibrium condition of the rolling moment is examined in various hand-launched take-off conditions. The results of this study demonstrate the importance of initial aileron deflection in increasing the initial rolling stability during the hand-launched take-off process. Furthermore, an aerodynamic database is constructed to rapidly predict the aileron set values required for different take-off speeds and angle-of-attacks.