• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.7
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• pp.543-552
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• 2013

For the safety messages in IEEE 802.11p/WAVE vehicles network environment, strict periodic beacon broadcasting requires status advertisement to assist the driver for safety. In crowded networks where beacon message are broadcasted at a high number of frequencies by many vehicles, which used for beacon sending, will be congested by the wireless medium due to the contention-window based IEEE 802.11p MAC. To resolve the congestion, we consider a MAC scheme based on slotted p-persistent CSMA as a simple non-cooperative Bayesian game which involves payoffs reflecting the attempt probability. Then, we derive Bayesian Nash Equilibrium (BNE) in a closed form. Using the BNE, we propose new congestion control algorithm to improve the performance of the beacon rate under saturation condition in IEEE 802.11p/WAVE vehicular networks. This algorithm explicitly computes packet delivery probability as a function of contention window (CW) size and number of vehicles. The proposed algorithm is validated against numerical simulation results to demonstrate its stability.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.11
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• pp.2745-2752
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• 2014

In recent years, Transport Demand Management has been conducted for the efficient management of transport. In ITS applications in particular, the prerequisite is accurate and reliable positioning. However, the major problems are satellite signal outage, and multipath. This paper proposes that outage and multipath measurement can be detected and estimated using elevation angle and signal to noise ratio data association relation in stand-alone GPS. In order to verify the performance of the proposed method, it is then evaluated by the car test. the evaluation test environment has low accuracy and unreliable positioning because of signal outage or multipath such as steep hill and high buildings. In the evaluation test result, 918times abnormal signal occurred and it was confirmed that the proposed method showed more improved 9.48m(RMS) horizontal positioning error than without proposed method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.223-227
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• 2006

The millimeter-wave radar is positioned as a key, basic ITS technology supporting safe driving, because millimeter wave allows radar to see small distant objects. This system is considered the collision-avoidance radar available in some cars. This system employs poised radar operating within the frequency range $76\sim77GHz$. Radar systems create two major problems(false images and system-to-system interference). False echoes cause driving hazards. These problems can be eliminated through the use of EM wave absorber. Therefore, we designed and fabricated EM wave absorber using permalloy. It has the thickness of 1.4 mm with composition of permalloy:CPE=70:30 wt% and absorption ability higher than 18 dB in the frequency range $76\sim77GHz$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.7
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• pp.977-985
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• 2021

The LiDAR sensor is attracting attention as a key sensor for autonomous driving vehicle. LiDAR sensor provides measured three-dimensional lengths within range using LASER. However, as much data is provided to the external system, it is difficult to process such data in an external system or processor of the vehicle. To resolve these issues, we develop integrated processing system for LiDAR sensor. The system is configured that client receives data from LiDAR sensor and processes data, server gathers data from clients and transmits integrated data in real-time. The test was carried out to ensure real-time processing of the system by changing the data acquisition, processing method and process driving method of process. As a result of the experiment, when receiving data from four LiDAR sensors, client and server process was operated using background or multi-core processing, the system response time of each client was about 13.2 ms and the server was about 12.6 ms.

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.12
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• pp.437-444
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• 2022

Recently, research on mobile edge services has been conducted to handle computationally intensive and latency-sensitive tasks occurring in wireless networks. However, MEC, which is fixed on the ground, cannot flexibly cope with situations where task processing requests increase sharply, such as commuting time. To solve this problem, a technology that provides edge services using UAVs (Unmanned Aerial Vehicles) has emerged. Unlike ground MEC servers, UAVs have limited battery capacity, so it is necessary to optimize energy efficiency through load balancing between UAV MEC servers. Therefore, in this paper, we propose a load balancing technique with consideration of the energy state of UAVs and the mobility of vehicles. The proposed technique is composed of task offloading scheme using genetic algorithm and task migration scheme using Q-learning. To evaluate the performance of the proposed technique, experiments were conducted with varying mobility speed and number of vehicles, and performance was analyzed in terms of load variance, energy consumption, communication overhead, and delay constraint satisfaction rate.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1307-1312
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• 2023

In this paper, we propose a hybrid camera system that combines cameras with different focal lengths and LiDAR (Light Detection and Ranging) sensors to address the core components of autonomous driving perception technology, which include object recognition and distance measurement. We extract objects within the scene and generate precise location and distance information for these objects using the proposed hybrid camera system. Initially, we employ the YOLO7 algorithm, widely utilized in the field of autonomous driving due to its advantages of fast computation, high accuracy, and real-time processing, for object recognition within the scene. Subsequently, we use multi-focal cameras to create depth maps to generate object positions and distance information. To enhance distance accuracy, we integrate the 3D distance information obtained from LiDAR sensors with the generated depth maps. In this paper, we introduce not only an autonomous vehicle platform capable of more accurately perceiving its surroundings during operation based on the proposed hybrid camera system, but also provide precise 3D spatial location and distance information. We anticipate that this will improve the safety and efficiency of autonomous vehicles.

• Journal of the Korea Society of Computer and Information
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• v.14 no.11
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• pp.105-111
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• 2009

The study aims to propose the intelligent clustering technique that calculates the distance by improving the problems of multi-hop clustering technique for inter-vehicular secure communications. After calculating the distance between vehicles with no connection for rapid transit and clustering it, the connection between nodes is created through a set distance vale. Header is selected by the distance value between nodes that become the identical members, and the information within a group is transmitted to the member nodes. After selecting the header, when the header is separated due to its mobility, the urgent situation may occur. At this time, the information transfer is prepared to select the new cluster header and transmit it through using the intelligent cluster provided from node by the execution of programs included in packet. The study proposes the cluster technique of the intelligent distance estimation for the mobile Ad-hoc network that calculates the cluster with the Store-Compute-Forward method that adds computing ability to the existing Store-and-Forward routing scheme. The cluster technique of intelligent distance estimation for the mobile Ad-hoc network suggested in the study is the active and intelligent multi-hop cluster routing protocol to make secure communications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.910-917
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• 2018

This paper describes the developments to improve the feeling and safety of the remote control system of unmanned vehicles. Generally, in the case of the remote control systems, a joystick-type device or a simple steering-wheel are used. There are many cases, in which there are operations without considering the feedback to users and driving feel. Recently, as the application area of the unmanned vehicles has been extended, the problems caused by not considering the feedback are emphasized. Therefore, the need for a force feedback-haptic control arises to solve these problems. In this study, the force feedback-haptic control algorithm considering the vehicle parameters is proposed. The vehicle parameters include first the state variables of dynamics, such as the body side-slip angle (${\beta}$) and yawrate (${\gamma}$), and second, the parameters representing the driving situations. Force feedback-haptic control technology consists of the algorithms for general and specific situations, and considers the situation transition process. To verify the algorithms, a simulator was constructed using the vehicle dynamics simulation tool with CAN communication environment. Using the simulator, the feasibility of the algorithms was verified in various scenarios.

• Electronics and Telecommunications Trends
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• v.29 no.5
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• pp.9-17
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• 2014

기존 자동차산업은 안전성과 편리성을 추구하는 소비자의 욕구에 부응하여 기계장치에서 전자장치로 변화하고 있다. 최근 IT기술과 산업 간 융합이 활발한 가운데 자동차 IT부문에도 각종 첨단 IT기술이 접목되면서 운전자의 안전 및 편의성을 증대시킬 수 있는 스마트카(Smart Car)로 진화하고 있다. 스마트카는 인포테인먼트와 텔레매틱스 뿐만 아니라 전기 전자시스템이 합쳐진 자동차로 사고 예방을 위한 첨단센서와 컴퓨팅기술, 차량주행 관리기술 및 음성인식기술 등이 있다. 이에 본고에서는 스마트카에 적용되는 첨단 IT기술과 최근 스마트카에 적용되는 첨단 자동차-IT 융합기술 및 서비스와 자동차 전자장치용 소프트웨어 표준 플랫폼인 AUTOSAR(AUTomotive Open System Architecture)의 표준동향 및 이슈를 살펴보고자 한다.

• Electronics and Telecommunications Trends
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• v.30 no.5
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• pp.11-21
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• 2015

최근 IT기술과 산업 간 융합이 활발한 가운데 자동차에도 각종 첨단 IT기술이 접목되면서 운전자의 안전과 편의성이 향상된 스마트카(smart car)가 속속 개발되고 있다. 가까운 미래에 스마트카의 도움으로 운전자가 전방주시 의무에서 자유롭게 될 수 있게 되면, 운행 중에 언제 어디서나 모바일 인터넷을 통한 정보접근이 가능하도록 지원하는 컴퓨팅 환경인 자동차 사물인터넷(Internet of Vehicles, Automotive IoT)이 중요하게 대두될 것으로 전망된다. 자동차 사물인터넷의 개념이 아직은 명확히 잡혀있지 않지만, 대체로 모바일 연결성(mobile connectivity)을 중심으로, 교통안전 혼잡해소뿐만 아니라 다양한 사용자 맞춤형 서비스 산업을 창출할 수 있는 컴퓨팅 환경을 의미한다. 즉, 운전자와 자동차, 자동차와 주변환경 및 교통인프라, 그리고 일상생활의 모든 요소가 자동차를 매개로 해서 유기적으로 연결되는 컴퓨팅 환경을 의미하며, 가까운 미래에 이런 컴퓨팅 환경을 지원하는 자동차가 상용화될 것으로 전망된다. 본고에서는 이러한 전망을 반영하여 자동차 사물인터넷 환경의 스마트카에 적용될 주요 기술과 서비스를 분석하고, 스마트카와 자율주행의 핵심기술인 인포테인먼트 플랫폼의 주요 동항 및 이슈를 살펴보고자 한다.