• The Journal of the Korea Contents Association
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• v.2 no.3
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• pp.113-118
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• 2002

To provide interactive sonics in HFC(Hybrid Fiber Coax)-CATV network, there must be supported a MAC(Medium Access Control) protocol. It is wet known that collision can be occurred in the HFC upstream channel because it is shared by up to 500 users. Thus it needs the collision resolution algorithm. Consequently, this paper proposes the analysis mood to study stability of binary stack algorithm for adaptive collision resolution algorithm in HFC-CATV. Also, it compares a system throughput between IPP model and D-BMAP model.

• Journal of Auto-vehicle Safety Association
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• v.11 no.3
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• pp.19-29
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• 2019

Recently, autonomous vehicles have been studied actively. Autonomous vehicles can detect objects around them using their on board sensors, estimate collision probability and maneuver to avoid colliding with objects. Many algorithms are suggested to prevent collision avoidance. However there are limitations of complex and diverse environments because algorithm uses only the information of attached environmental sensors and mainly depends on TTC (time-to-Collision) parameter. In this paper, autonomous driving algorithm using I2V communication-based cooperative sensing information is developed to cope with complex and diverse environments through sensor fusion of objects information from infrastructure camera and object information from equipped sensors. The cooperative sensing based autonomous driving algorithm is implemented in autonomous shuttle bus and the proposed algorithm proved to be able to improve the autonomous navigation technology effectively.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.238-246
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• 2021

Collision of small vessels such as fishing boats cause great personal injury. Prior to this study, the collision prevention algorithm was developed to assess the collision risk and make the collision alarm. However, a service provided for safety, such as a collision warning, not only prevents risks, but also requires a certain degree of user satisfaction to function effectively. In this study, the collision prevention algorithm for small vessels was improved to be more practical, and the effects of the improvement were confirmed by applying the algorithm. A survey conducted on the users of the collision warning service confirmed the user requirements for improving the accuracy of the collision warning system and reducing the volume and number of alarms. Accordingly, the algorithm was improved for user satisfaction, and the actual vessel experiment was performed applying the improved algorithm in an actual maritime environment. As a result, the frequency of alarm occurrence decreased compared to former algorithm, but the alarm was relatively steadily generated in dangerous situations. It was analyzed that the accuracy and practicality of the collision alarm were improved. If the practicality and reliability of the improved algorithm are verified in the further study, it will be able to effectively contribute to the prevention of collisions of small vessels.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.3
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• pp.413-420
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• 2006

In this thesis, a RFID baseband system is implemented based on the international standard ISO/IEC 18000-6 Type-B using FPCA, and also anti-collision algorithm is implemented to improve the system performance. We compares the performance of the proposed anti-collision algorithm with that binary tree algorithm and bit-by-bit algorithm, and also validated analytic results using OPNET simulation. The proposed algorithm for Type-B transmission protocol and collision prohibition was designed using ISE7.1i which is a FPGA design-tool of Xilinx and implemented with Spartan2 chip which is a FPGA device.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.2
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• pp.169-177
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• 2019

It is very important to understand the intention of a target ship to prevent collisions in multiple-ship situations. However, considering the intentions of a large number of ships at the same time is a great burden for the officer who must establish a collision avoidance plan. With a distributed algorithm, a ship can exchange information with a large number of target ships and search for a safe course. In this paper, I have applied a Distributed Stochastic Search Algorithm (DSSA), a distributed algorithm, for ship collision avoidance. A ship chooses the course that offers the greatest cost reduction or keeps its current course according to probability and constraints. DSSA is divided into five types according to the probability and constraints mentioned. In this paper, the five types of DSSA are applied for ship collision avoidance, and the effects on ship collision avoidance are analyzed. In addition, I have investigated which DSSA type is most suitable for collision avoidance. The experimental results show that the DSSA-A and B schemes offered effective ship collision avoidance. This algorithm is expected to be applicable for ship collision avoidance in a distributed system.

• The Journal of Korea Robotics Society
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• v.12 no.3
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• pp.258-262
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• 2017

In this paper, we propose a new collision detection algorithm for human-robot collaboration. We use an IMU sensor located at the tip of the manipulator and the kinematic behavior of the manipulator to detect the unexpected collision between the robotic manipulator and environment. Unlike other method, the developed algorithm uses only the kinematic relationship between the manipulator joint and the end effector. Therefore, the collision estimation signal is not affected by the error of the dynamics model. The proposed collision detection algorithm detects the collision by comparing the estimated acceleration of the end effector derived from the position, velocity and acceleration trajectories of the robot joints with the actual acceleration measured by the sensor. In simulation, we compare the performance of our method with the conventional Residual Observer (ROB). Our method is less sensitive to the load variation because of the independency on the dynamic modeling of the manipulator.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.10
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• pp.996-1002
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• 2008

This paper presents the development of a real-time algorithm for collision detection, collision avoidance and guidance to way-point. Three-dimensional point-mass aircraft models are used. For collision detection, time of closest point of approach(CPA) and distance at CPA are compared to threshold values. For collision avoidance, optimal acceleration input which maximizes the terminal relative distance is calculated based on optimal control theory. For guidance to way-point, proportional navigation guidance, the well-known method, is used. Two scenarios of encounter situation are illustrated to validate performance of proposed algorithm.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.2 no.6
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• pp.299-311
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• 2008

The Radio Frequency IDentification (RFID) system is a contactless automatic identification system, which comprises readers and tags. In RFID systems, a reader collision occurs when there is interference in communication between one reader and the tags, due to the signals from other readers. The reader collision problem is considered as the fundamental problem affecting high density RFID reader installations. In this paper, we analyze the existing reader anti-collision algorithms. We also propose a pulse protocol-based reader anti-collision algorithm using slot occupied probability (SOP). The implementation of this improvement is simple, yet it effectively mitigates most reader collisions in dense reader mode, as shown in our simulation. That is, the proposed algorithm reduces the identification time, and increasesthe system throughput and system efficiency compared with the conventional reader anti-collision algorithms.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.1
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• pp.99-108
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• 2010

RFID(Radio Frequency IDentification) is a technology that automatically identifies objects containing the electronic tags by using radio wave. When there are some tags in the domain of the RFID reader, the mechanism that can solve a collision between the tags occurs is necessary. The multi tag identification problem is the core issue in the RFID and could be resolved by the anti-collision algorithm. However, RFID system has another problem. The problem id user information security. Tag response easily by query of reader, so the system happened user privacy violent problem by tag information exposure. In the case, RFID system id weak from sniffing by outside. In this paper, We study of security robustness for tree-walking algorithm, query tree algorithm and advanced query tree algorithm of tree based memoryless algorithm.

• Journal of Korea Game Society
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• v.12 no.4
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• pp.23-31
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• 2012

The collision processing is one of the essential factors to realize physical principles in the game, and it gives liveliness to the game. The collision processing requires a large amount of operations, and significantly affects the game performance. To address this problem, many studies have been conducted to reduce the operation volume, and the SAP algorithm is being widely used. However, its efficiency is low because it involves repetitive operations. In this study, a distance-based SAP algorithm was proposed to reduce the operation volume for the collision processing and address the problem of the SAP algorithm. A test was conducted to measure the FPS using the simulation program, which was developed with the proposed algorithm. The FPS was 2-33 times higher with the proposed algorithm, which indicated that the efficiency of the collision processing was improved.