• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.3
• /
• pp.1681-1684
• /
• 2014

In this paper, in the ventilation system of coal-fired power boilers can measure in real time the fan stall mechanism is all about. The fan stall guard system of boiler airing system of the class of 500MW capacity to protect fan. But because confidence is loosed and operation is influenced by frequent fault of fan stall guard system, confidence is improved by substituting DCS Logic for it.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.55 no.3
• /
• pp.119-123
• /
• 2006

The orthogonal frequency-division multiplexing (OFDM) technique is well known to be robust against the frequency-selective fading in wireless channels. It is due to the exploitation of a guard interval that is inserted at beginning of each OFDM symbol. Based on the conventional OFDM and a polyphase filtered orthogonal frequency division multiplexing (PF-OFDM) technique, we developed an adaptive beamforming algorithm for antenna arrays. The proposed algorithm would lead to an efficient use of channel, since it is possible to eliminate a guard interval and also easily suppress interchannel interference at the same time. In this paper, a series of computer simulations have been provided to show the performance of the proposed system.

• Proceedings of KOSOMES biannual meeting
• /
• 2017.11a
• /
• pp.130-130
• /
• 2017

• Proceedings of the Korea Information Processing Society Conference
• /
• 2024.05a
• /
• pp.327-328
• /
• 2024

본 논문에서는 DarkWebGuard라는 실시간 악성 URL 탐지 시스템을 소개하고, 그 개발에 사용된 도구와 알고리즘에 대해 논의합니다. DarkWebGuard는 머신러닝을 기반으로 하며, 인터넷 보안에 대한 현재의 요구를 충족시키기 위해 개발되었습니다. 이 시스템은 사용자와 시스템을 보호하기 위해 악성 URL을 실시간으로 탐지하고 분류합니다.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.4 no.3
• /
• pp.643-652
• /
• 2000

In this paper, we analyze the BER performance of OFDM/QPSK system in frequency selective Rayleigh fading channel with impulsive noise and improve its performance by adopting convolutional coding. When the channel delay time is shorter than the guard band, the OFDM/QPSK system shows a good BER performance while, when the channel delay time becomes longer than the guard band, its BER performance is abruptly degraded. Moreover, when the transmitted signal is contaminated by a strong impulsive noise in the channel, the BER performance falls to about $10^{-1}$. Also, without channel coding technique, the system doesn't meet even the voice service requirement while it meets the data service requirement with convolutional coding in frequency selective Rayleigh fading channel with impulsive noise.

• Journal of the Society of Disaster Information
• /
• v.5 no.1
• /
• pp.104-119
• /
• 2009

The purpose of this study is to examine the effects of job involvement and organization commitment on job form of security guard. The total 260 subjects are composed of 50 women and 210 men who work at security company for security guards in Seoul and Gyonggi province. First, according to the populational and social character, job involvement was higher in women security guards than men, higher in 'above 41' for age, higher in 'university' for educational level, and higher in '300-400' for incomes. Second, according to the populational and social character, organization commitment was higher in men security guards than women, higher in 'above 41 ' for age, higher in 'graduate school of university' for educational level, and higher in '300-400' for incomes. Third, according to the form of the job, the job involvement was higher in 'under 10' for their career, higher in 'manager' for their responsibilities of work, higher in 'afternoon working' for the time schedules, and higher in 'field service' for the kind of working. Fourth, according to the form of the job, the organization commitment was higher in 'under 10' for their career and higher in 'field service' for the kind of working. However, there was no difference between the responsibilities of work and the time schedules. Fifth, it increases the organization, when the job involvement of the security guards such as work attachment, active performance, and the pursuit of job achievement.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.10
• /
• pp.2088-2096
• /
• 2009

This paper deals with hybrid MAC protocol design for underwater acoustic networks. The proposed MAC protocol has the cluster structure with a master node and slave nodes, and the hybrid network structure that combines a contention free period based on TDMA(Time Division Multiple Access) with a contention period. The suggested MAC protocol has a beacon packet for supervising network, a guard period between time slots for packet collision, time tag for estimation of propagation delay with a master node, the time synchronization of nodes, entering and leaving of network, and the communication method among nodes. In this paper, we adapt the proposed hybrid MAC protocol to AUV network, that is the representative mobile device of underwater acoustic network, and verify this protocol is applicable in real underwater acoustic network environment.

• Korean Journal of Applied Biomechanics
• /
• v.12 no.2
• /
• pp.215-227
• /
• 2002

The purpose of this study was to investigate propulsive time and kinematic variables on the three different kinds of the basketball wheelchairs in each play position for eight abled basketball wheelchair players. Kinematic data were collected by a video camera for two-dimensional analysis. The wheelchairs for the guard position showed the fastest in total propulsive time. The wheelchairs for the center position revealed the slowest in the phase of the change of the direction. The wheelchair for the guard position which shows fast movement velocity demonstrated closer hand contact with TDC(Top Dead Center). The wheelchair for the center position revealed the largest extension of the elbow and flexion of the trunk at handrim contact. The wheelchair for the guard position which has the lowest seat height presented larger elbow angle and trunk angle. The wheelchair for the guard position produced more fast trunk angular velocity than the wheelchair for other positions.

• Journal of KIISE:Information Networking
• /
• v.30 no.4
• /
• pp.461-473
• /
• 2003

Multimedia applications are much more sensitive to QoS(Quality of Service) than text based ones due to their data continuity. In order to provide a fast moving MH(Mobil Host) using multimedia application with a consistent QoS,an efficient call admission mechanism is in need. This paper proposes the 2SCA(2-Step Call Admission) scheme based on cal admission scheme using pripority to guarantee the consistent QoS for mobile multimedia applications. A calls of MH are classified new calls, hand-off calls, and QoS upgrading calls. The 2SCA is composed of the basic call admission and advanced call admission; the former determines the call admission based on bandwidth available in each cell and the latter determines the call admission by applying DTT(Delay Tolerance Time), PQeueu(Priority Queue), and UpQueue(Upgrade Queue) algorithm according to the type of each call blocked at the basic call admission stage. In order to evaluate the performance of our mechanism, we measure the metrics such as the dropping probability of new calls, dropping probability of hand-off calls, and bandwidth utilization. The result shows that the performance of our mechanism is superior to that of existing mechanisms such as CSP(Complete Sharing Policy), GCP(Guard Channel Policy) and AGCP(Adaptive Guard Channel Policy).

• KIPS Transactions on Computer and Communication Systems
• /
• v.11 no.10
• /
• pp.345-352
• /
• 2022

Recent LiDAR(Light Detection And Ranging) sensor is used for scanning object around in real-time. This sensor can detect movement of the object and how it has changed. As the production cost of the sensors has been decreased, LiDAR begins to be used for various industries such as facility guard, smart city and self-driving car. However, LiDAR has a large input data size due to its real-time scanning process. So another way for processing a large amount of data are needed in LiDAR system because it can cause a bottleneck. This paper proposes edge computing to compress massive point cloud for processing quickly. Since laser's reflection range of LiDAR sensor is limited, multiple LiDAR should be used to scan a large area. In this reason multiple LiDAR sensor's data should be processed at once to detect or recognize object in real-time. Edge computer compress point cloud efficiently to accelerate data processing and decompress every data in the main cloud in real-time. In this way user can control LiDAR sensor in the main system without any bottleneck. The system we suggest solves the bottleneck which was problem on the cloud based method by applying edge computing service.