• Title/Summary/Keyword: Low-end System

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VHF Relay Network for Long Air-to-Ground Communication in Oceanic Flight Routes (대양항로에서 장거리 공대지통신을 위한 VHF Relay Network)

  • Koo, Jayeul
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.20 no.3
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    • pp.22-27
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    • 2012
  • In oceanic flight routes, HF radio and satellite data links have been used for air-to-ground communication, but these systems have long propagation delay and low data throughput. In this paper, we propose a reliable system to overcome the weakness of current HF radio and satellite communication systems for oceanic aeronautical flight routes. The proposed scheme uses only one aeronautical VHF channel in multi-hop oceanic communication environments and supports a hybrid type of multiple access, which consists of random access and TDMA (Time Division Multiple Access) scheme. The proposed system improves performance on delay and throughput as an effective solution to communicate end-to-end on the oceanic flight routes and strengthens the reliability of oceanic aeronautical communication.

Implementation of Low Loss Radome with Hexa mesh for Ku-Band

  • Seo, Kang;JeongJin, Kang
    • International Journal of Advanced Culture Technology
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    • v.10 no.4
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    • pp.555-560
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    • 2022
  • In this study, the insertion loss and phase delay according to the multi-layer structure radome parameters were analyzed using the boundary value solution approach, and the multi-layer structure and hexa mesh structures with low-loss electrical characteristics for the Ku-band transmission/reception frequency of 10.7 ~ 14.5 GHz were designed and manufactured. A hexa mesh was applied to minimize radio wave transmission and scattering, which lowered the transmittance refractive index according to the radio incident angle and minimized dielectric loss through high-density foam. Similar to the simulation result, the transmission loss obtained the gain in a specific receiving frequency band, and in the transmission frequency band, an excellent low loss characteristic was obtained with an insertion loss of 0.8dB or less. The results of this study can be used in radio transmission radomes of low-weight, low-cost end-system protection devices.

A Study on the Implementation of Intelligent Diagnosis System for Motor Pump (모터펌프의 지능형 진단시스템 구현에 관한 연구)

  • Ahn, Jae Hyun;Yang, Oh
    • Journal of the Semiconductor & Display Technology
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    • v.18 no.4
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    • pp.87-91
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    • 2019
  • The diagnosis of the failure for the existing electrical facilities was based on regular preventive maintenance, but this preventive maintenance was limited in preventing a lot of cost loss and sudden system failure. To overcome these shortcomings, fault prediction and diagnostic techniques are critical to increasing system reliability by monitoring electrical installations in real time and detecting abnormal conditions in the facility early. As the performance and quality deterioration problem occurs frequently due to the increase in the number of users of the motor pump, the purpose is to build an intelligent control system that can control the motor pump to maximize the performance and to improve the quality and reliability. To this end, a vibration sensor, temperature sensor, pressure sensor, and low water level sensor are used to detect vibrations, temperatures, pressures, and low water levels that can occur in the motor pump, and to build a system that can identify and diagnose information to users in real time.

Deep compression of convolutional neural networks with low-rank approximation

  • Astrid, Marcella;Lee, Seung-Ik
    • ETRI Journal
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    • v.40 no.4
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    • pp.421-434
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    • 2018
  • The application of deep neural networks (DNNs) to connect the world with cyber physical systems (CPSs) has attracted much attention. However, DNNs require a large amount of memory and computational cost, which hinders their use in the relatively low-end smart devices that are widely used in CPSs. In this paper, we aim to determine whether DNNs can be efficiently deployed and operated in low-end smart devices. To do this, we develop a method to reduce the memory requirement of DNNs and increase the inference speed, while maintaining the performance (for example, accuracy) close to the original level. The parameters of DNNs are decomposed using a hybrid of canonical polyadic-singular value decomposition, approximated using a tensor power method, and fine-tuned by performing iterative one-shot hybrid fine-tuning to recover from a decreased accuracy. In this study, we evaluate our method on frequently used networks. We also present results from extensive experiments on the effects of several fine-tuning methods, the importance of iterative fine-tuning, and decomposition techniques. We demonstrate the effectiveness of the proposed method by deploying compressed networks in smartphones.

A Study on Restraint Effects of Head Restraint Systems and Neck Injuries in Rear-End Crash (추돌시 Head Restraints 시스템의 구속 효과와 인체 상해에 관한 연구)

  • Lee, Chang-Min
    • Journal of the Ergonomics Society of Korea
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    • v.17 no.3
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    • pp.1-11
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    • 1998
  • Focuses of this study are to investigate the usage status of head-restraint system(H/R) in usual driving and to simulate usage conditions of H/R at rear-end crashes. The usage of H/R was categorized into five classes according to the height and distance from occupant's head ; Large-$90^{\circ}$ H/R for enough height and short distance. Large-$70^{\circ}$ H/R for enough height and long distance. Small-$90^{\circ}$ H/R for low height and short distance. Small-$70^{\circ}$ H/R for low height and long distance. and No H/R. Then. these five conditions were tested to find out the degree of neck injuries by using a car-crash simulation package, DYNAMAN. Results from the investigation of H/R usage show that most of drivers(60%) have Small-$70^{\circ}$ H/R for low height and long distance. Results from the simulation performed at 15mph and 30mph show that: 1) at 15 mph, there is a possibility for neck injury in Small-$90^{\circ}$ H/R and Small-$70^{\circ}$ H/R. 2) at 30 mph. there is a high possibility of death in Small-$70^{\circ}$ H/R and Small-$90^{\circ}$ H/R.

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Unethical Network Attack Detection and Prevention using Fuzzy based Decision System in Mobile Ad-hoc Networks

  • Thanuja, R.;Umamakeswari, A.
    • Journal of Electrical Engineering and Technology
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    • v.13 no.5
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    • pp.2086-2098
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    • 2018
  • Security plays a vital role and is the key challenge in Mobile Ad-hoc Networks (MANET). Infrastructure-less nature of MANET makes it arduous to envisage the genre of topology. Due to its inexhaustible access, information disseminated by roaming nodes to other nodes is susceptible to many hazardous attacks. Intrusion Detection and Prevention System (IDPS) is undoubtedly a defense structure to address threats in MANET. Many IDPS methods have been developed to ascertain the exceptional behavior in these networks. Key issue in such IDPS is lack of fast self-organized learning engine that facilitates comprehensive situation awareness for optimum decision making. Proposed "Intelligent Behavioral Hybridized Intrusion Detection and Prevention System (IBH_IDPS)" is built with computational intelligence to detect complex multistage attacks making the system robust and reliable. The System comprises of an Intelligent Client Agent and a Smart Server empowered with fuzzy inference rule-based service engine to ensure confidentiality and integrity of network. Distributed Intelligent Client Agents incorporated with centralized Smart Server makes it capable of analyzing and categorizing unethical incidents appropriately through unsupervised learning mechanism. Experimental analysis proves the proposed model is highly attack resistant, reliable and secure on devices and shows promising gains with assured delivery ratio, low end-to-end delay compared to existing approach.

Implementation and Evaluation of Proxy Caching Mechanisms with Video Qualify Adjustment

  • Sasabe, Masahiro;Taniguchi, Yoshiaki;Wakamiya, Naoki;Murata, Masayuki;Miyahara, Hideo
    • Proceedings of the IEEK Conference
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    • 2002.07a
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    • pp.121-124
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    • 2002
  • The proxy mechanism widely used in WWW systems offers low-delay data delivery by means of "proxy server". By applying the proxy mechanisms to the video streaming system, we expect that high-quality and low-delay video distribution can be accomplished without introducing extra load on the system. In addition, it is effective to adapt the quality of cached video data appropriately in the proxy if user requests are diverse due to heterogeneity in terms of the available bandwidth, end-system performance, and user′s preferences on the perceived video quality. We have proposed proxy caching mechanisms to accomplish the high-quality and highly-interactive video streaming services. In our proposed system, a video stream is divided into blocks for efficient use of the cache buffer. The proxy server is assumed to be able to adjust the quality of a cached or retrieved video block to the request through video filters. In this paper, to verify the practicality of our mechanisms, we implemented them on a real system and conducted experiments. Through evaluations from several performance aspects, it was shown that our proposed mechanisms can provide users with a low-latency and high-quality video streaming service in a heterogeneous environment.

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Design and Implementation of e2eECC for Automotive On-Chip Bus Data Integrity (차량용 온칩 버스의 데이터 무결성을 위한 종단간 에러 정정 코드(e2eECC)의 설계 및 구현)

  • Eunbae Gil;Chan Park;Juho Kim;Joonho Chung;Joosock Lee;Seongsoo Lee
    • Journal of IKEEE
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    • v.28 no.1
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    • pp.116-122
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    • 2024
  • AMBA AHB-Lite bus is widely used in on-chip bus protocol for low-power and cost-effective SoC. However, it lacks built-in error detection and correction for end-to-end data integrity. This can lead to data corruption and system instability, particularly in harsh environments like automotive applications. To mitigate this problem, this paper proposes the application of SEC-DED (Single Error Correction-Double Error Detection) to AMBA AHB-Lite bus. It aims not only to detect errors in real-time but also to correct them, thereby enhancing end-to-end data integrity. Simulation results demonstrate real-time error detection and correction when errors occur, which bolsters end-to-end data integrity of automotive on-chip bus.

A novel three-phase power system for a simple photovoltaic generator (태양광발전을 위한 새로운 3상한 시스템에 관한 연구)

  • Park, Sung-Joon;Kim, Jung-Hun;Kim, Jin-Young;Kim, Jeoung-Hyun;Kim, Hee-Je
    • 한국신재생에너지학회:학술대회논문집
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    • 2005.06a
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    • pp.181-184
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    • 2005
  • Operating conditions of photovoltaic power generator is very sensitive to the PV modules. The PV module's control is an importance issue in the removing DC ripple noise. In this paper, the phase-shifted-carrier technique, which is a new three-step dc-dc power multi-converter schemes, is applied to solar generator system to improve the output current waveform. The novel type of three-step dc-dc converter presented has many features such as the good output waveform, high efficiency, low switching losses, low acoustic noise. The circuit configuration is constructed by the conventional full-bridge type converter circuit using the isolated DC power supply for which the solar cell is very suitable. In the end, a circuit design for understanding three-step dc-dc converter and new solar power system were presented

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Simultaneous measurement of oxygen permeability by using of multi-functional oxygen electrode (다기능 산소전극에 의한 산소투과특성 동시측정)

  • 이동희;정진휘;유형풍;김태진
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.532-535
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    • 2000
  • We have fabricated a sensor system for on-line monitoring the oxygen permeability and diffusivity of six different polymer films using the miniaturized 6 cathode(Ag)-single anode(Ag/AgCl) type hexagonal oxygen electrode. This system consists of multiple input front-end electronics, signal conditioning circuit using the embedded microcontroller 80C196KC, PC interface circuit and PC with the OS for microcontroller and the operating program for this system. The digital low-[ass filter was programmed and the simulated filter characteristics were enough to eliminate the noise from sensor signal. According to the experimental results, the linearity coefficients of the output voltage to oxygen partial pressure for each sensor electrode of six cathode type oxygen sensor are 0.998, 0.997, 0.998, 0.997, 0.997, 0.997 respectively, and the response times are all within 4 minutes.

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