무선 Content-Centric Network에서 Data 확산 제한 방법

박찬민,김병서,Park, Chan-Min,Kim, Byung-Seo 대한임베디드공학회 2016 대한임베디드공학회논문지 Vol.11 No.1

Since Devices such labtop, tablet, smartphone have been developed, a lots of huge data that can be classified as content is flooded in the network. According to changing Internet usage, Content-Centric Network(CCN) what is new concept of Internet Architecture is appeared. Initially, CCN is studied on wired network. but recently, CCN is also studied on wireless network. Since a characteristic of wireless environment is different from a characteristic of wired environment, There are issues in wireless CCN. In this paper, we discuss improvement method of Data spread issue on wireless CCN. The proposed scheme of this paper use MAC Address of nodes when Interest and Data Packet are forwarded. As using the proposed scheme, we reduce the spread of Data and offer priority of forwarding to nodes of shortest path, reduce delay by modifying retransmission waiting time.

무게-가변형 드론을 위한 동역학 기반 시뮬레이터 개발

백금봉,김정환,김식 대한임베디드공학회 2020 대한임베디드공학회논문지 Vol.15 No.3

Regarding previously-developed drone simulators, it was easy to check their flight stability or controlling functions based on the condition that their weight was fixed from the design. However, the drone is largely classified into two types that is the one with the fixed weight whose purpose is recording video with camera and racing and another is whole weight-variable during flight with loading the articles for delivery and spraying pesticide though the weight of airframe is fixed. The purpose of this thesis is to analyze the structure of drone and its flight principle, suggest dynamics-model-based simulator that is capable of simulating weight-variable drone and develop the simulator that can be used for designing main control board, motor and transmission along the application of weight-variable drone. Weight-variable simulator was developed by using various calculation to apply flying method of drone to the simulator. First, ground coordinate system and airframe-fixing coordinate system were established and switching matrix of those two coordinates were made. Then, dynamics model of drone was established using the law of Newton and moment balance principle. Dynamics model was established in Simulink platform and simulation experiment was carried out by changing the weight of drone. In order to evaluate the validity of developed weight-variable simulator, it was compared to the results of clean flight public simulator against existing weight-fixed drone. Lastly, simulation test was performed with the developed weight-variable simulation by changing the weight of drone. It was found out that dynamics model controlled various flying positions of drone well from simulation and the possibility of securing the optimum condition of weight-variable drone that has flying stability and easiness of controlling. Regarding previously-developed drone simulators, it was easy to check their flight stability or controlling functions based on the condition that their weight was fixed from the design. However, the drone is largely classified into two types that is the one with the fixed weight whose purpose is recording video with camera and racing and another is whole weight-variable during flight with loading the articles for delivery and spraying pesticide though the weight of airframe is fixed. The purpose of this thesis is to analyze the structure of drone and its flight principle, suggest dynamics-model-based simulator that is capable of simulating weight-variable drone and develop the simulator that can be used for designing main control board, motor and transmission along the application of weight-variable drone. Weight-variable simulator was developed by using various calculation to apply flying method of drone to the simulator. First, ground coordinate system and airframe-fixing coordinate system were established and switching matrix of those two coordinates were made. Then, dynamics model of drone was established using the law of Newton and moment balance principle. Dynamics model was established in Simulink platform and simulation experiment was carried out by changing the weight of drone. In order to evaluate the validity of developed weight-variable simulator, it was compared to the results of clean flight public simulator against existing weight-fixed drone. Lastly, simulation test was performed with the developed weight-variable simulation by changing the weight of drone. It was found out that dynamics model controlled various flying positions of drone well from simulation and the possibility of securing the optimum condition of weight-variable drone that has flying stability and easiness of controlling.

스테레오 영상 보행자 인식 시스템의 후보 영역 검출을 위한 GP-GPU 기반의 효율적 구현

정근용,정준희,이희철,전광길,조중휘,Jeong, Geun-Yong,Jeong, Jun-Hee,Lee, Hee-Chul,Jeon, Gwang-Gil,Cho, Joong-Hwee 대한임베디드공학회 2013 대한임베디드공학회논문지 Vol.8 No.2

There have been various research efforts for pedestrian recognition in embedded imaging systems. However, many suffer from their heavy computational complexities. SVM classification method has been widely used for pedestrian recognition. The reduction of candidate region is crucial for low-complexity scheme. In this paper, We propose a real time HOG based pedestrian detection system on GPU which images are captured by a pair of cameras. To speed up humans on road detection, the proposed method reduces a number of detection windows with disparity-search and near-search algorithm and uses the GPU and the NVIDIA CUDA framework. This method can be achieved speedups of 20% or more compared to the recent GPU implementations. The effectiveness of our algorithm is demonstrated in terms of the processing time and the detection performance.

차량 속도 기반 정확도 제어를 통한 차량용 LiDAR 센서의 효율적 전력 절감 기법

이상훈,이동규,최평,박대진 대한임베디드공학회 2020 대한임베디드공학회논문지 Vol.15 No.5

Light detection and ranging (LiDAR) sensors detect the distance of the surrounding environment and objects. Conventional LiDAR sensors require a certain amount of a power because they detect objects by transmitting lasers at a regular interval depending on a constant resolution. The constant power consumption from operating multiple LiDAR sensors is detrimental to autonomous and electric vehicles using battery power. In this paper, we propose two algorithms that improve the inefficient power consumption during the constant operation of LiDAR sensors. LiDAR sensors with algorithms efficiently reduce the power consumption in two ways: (a) controlling the resolution to vary the laser transmission period ( ) of a laser diode (LD) depending on the vehicle’s speed and (b) reducing the static power consumption using a sleep mode depending on the surrounding environment. A proposed LiDAR sensor with a resolution control algorithm reduces the power consumption of the LD by 6.92% to 32.43% depending on the vehicle’s speed, compared to the maximum number of laser transmissions (   ). The sleep mode with a surrounding environment-sensing algorithm reduces the power consumption by 61.09%. The proposed LiDAR sensor has a risk factor for 4-cycles that does not detect objects in the sleep mode, but we consider it to be negligible because it immediately switches to an active mode when a change in surrounding conditions occurs. The proposed LiDAR sensor was tested on a commercial processor chip with the algorithm controlling the resolution according to the vehicle’s speed and the surrounding environment.

SNOMED CT 브라우저에서 검색 결과의 재구성 기법

류우석,Ryu, Wooseok 대한임베디드공학회 2015 대한임베디드공학회논문지 Vol.10 No.3

SNOMED CT browser is a browsing tool for searching clinical terms in SNOMED CT which is a standard terminology set used worldwide. The search result view of previous browsers merely list up candidate terminologies. The problem is that most of users become confused about how to select an appropriate term from the list. This leads serious waste of medical recoding cost. This paper discusses characteristics of SNOMED CT dataset and proposes a novel design of enhanced result view by restructuring the results using relationships of SNOMED CT concepts. Using the proposed scheme, medical doctors or officers can select appropriate terms more efficiently and can reduce overall recording time.

지그비 기반의 실시간 무선 네트워크 모터 제어시스템

박정일,Park, Jung-Il 대한임베디드공학회 2020 대한임베디드공학회논문지 Vol.15 No.2

This paper finds solutions for using ZigBee in wireless networked control system (WNCS). The round trip time delay and packet loss rate of the WNCS are measured. On the basis of these measured data, a playback buffer is used to solve the variable time delay in WNCS, and a Smith predictor is introduced to compensate for the time delay. The WNCS was able to be actually constructed to perform DC motor position control with 40 Hz sampling frequency.

플래시 디스크 기반 행렬전치 알고리즘 심층 분석 및 성능개선

이형봉,정태윤 대한임베디드공학회 2017 대한임베디드공학회논문지 Vol.12 No.6

The scope of the matrix application is so broad that it can not be limited. A typical matrix application area in computer science is image processing. Particularly, radar scanning equipment implemented on a small embedded system requires real-time matrix transposition for image processing, and since its memory size is small, a general matrix transposition algorithm can not be applied. In this case, matrix transposition must be done in disk space, such as flash disk, using a limited memory buffer. In this paper, we analyze and improve a recently published flash disk-based matrix transposition algorithm named as asymmetric sub-matrix transposition algorithm. The performance analysis shows that the asymmetric sub-matrix transposition algorithm has lower performance than the conventional sub-matrix transposition algorithm, but the improved asymmetric sub-matrix transposition algorithm is superior to the sub-matrix transposition algorithm in 13 of the 16 experimental data.

가상 프로토타입 기반 임베디드 소프트웨어의 테스트 기법

류호동,정수용,이성희,김지훈,박흥준,이승민,이우진 대한임베디드공학회 2014 대한임베디드공학회논문지 Vol.9 No.6

Recently, software reliability and safety issues are seriously considered since failures of embedded systems may cause the damages of human lifes. For verifying and testing embedded software, execution environment including sensors and actuators should be prepared in the actual plants or virtual forms on PC. In this paper, we provide the virtual prototype based code simulation techniques and testing framework on PC. Virtual prototypes are generated by combining the Adobe’s Flash SWF images corresponding to the state machine of HW or environment components. Code simulation on PC is possible by replacing the device drivers into virtual drivers which connect to virtual prototypes. Also, testing is performed by controlling the states of virtual prototype and simulators. By using these tools, embedded software can be executed in the earlier development phase and the efficiency and SW quality can be enhanced.

프레임률을 고려한 항공기 시뮬레이터의 영상 동기화 방안

이순영,문대환,이충재,김기일,Lee, SunYoung,Mun, Dae-Han,Lee, ChungJae,Kim, Ki-Il 대한임베디드공학회 2016 대한임베디드공학회논문지 Vol.11 No.1

According to general architecture of flight simulator made up of several independent rendering display systems, display synchronization problem between them naturally happens. In addition, since the flight simulator is usually implemented in the same networks where network delay is not big concern, it is necessary to consider different factors of existing synchronization technique. Among them, in this paper, we propose a new display synchronization scheme for flight simulator where each system has different rendering capacity. In the proposed scheme, each system is synchronized by considering maximum and minimum frames per second (FPS) while considering level of detail and latency. Also, experimental results are given to demonstrate the suitability of the proposed scheme for display synchronization scheme.

실수값 복원키를 이용한 광 영상 은닉 기술

조규보,서동환,최은창,Cho, Kyu-Bo,Seo, Dong-Hoan,Choi, Eun-chang 대한임베디드공학회 2011 대한임베디드공학회논문지 Vol.6 No.3

In this paper, an optical image hiding technique using real-valued decoding key is proposed. In the embedding process, a each zero-padded original image placed in a quadrants on an input plane is multiplied by a statistically independent random phase pattern and is Fourier transformed. An encoded image is obtained by taking the real-valued data from the Fourier transformed image. And then a phase-encoded pattern, used as a hidden image and a decoding key, is generated by the use of multiple phase wrapping from the encoded images. A transmitted image is made from the linear superposition of the weighted hidden images and a cover image. In reconstruction process, the mirror reconstructed images can be obtained at two quadrants by the inverse-Fourier transform of the product of the transmitted image and the decoding key. Computer simulation and optical experiment are demonstrated in order to confirm the proposed technique.