• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.3
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• pp.1031-1046
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• 2018

Vehicular ad hoc network (VANET) is a dedicated network to connect vehicles without any centralized administration or infrastructure. The wireless access in vehicular environments (WAVE) protocol leveraging IEEE 1609/802.11p is widely implemented for VANETs. However, in congested traffic situation, the performance of the WAVE system degrades significantly due to serious collision, especially for safety related broadcast services on the control channel (CCH) interval due to the inherent drawback of its collision avoidance mechanisms called carrier sense multiple access with collision avoidance (CSMA/CA). In this paper, we propose a method that can decrease the number of frame collisions in CCH with a few modifications to the IEEE 802.11p protocol. In the paper, vehicles still employ CSMA/CA to compete for the channel access opportunity. However, by taking advantage of periodicity of synchronization interval, a two-state switching scheme introducing two new inter frame space (IFS) is proposed to reduce the number of competing vehicles substantially and as a result, the collision probability is significantly decreased. The simulation results demonstrate the superiority of the proposed method in packet collision rate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.9A
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• pp.920-927
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• 2006

There are three critical considerations in developing a PCM telemetry encoder to be installed in an artillery projectile. The first is the performance consideration, such as sampling rate and data transmission rate. The second is the size consideration due to the severely limited installation space in an artillery projectile and the last is the power consumption consideration due to limitations of the munition's power supply. To meet these three considerations, the best alternative is a one-chip solution. Using a commercially available TMS320F2812 DSP, we have implemented a 30-channel PCM telemetry encoder to process randomized data frames, composed of 16-channel analog data, 14-channel digital data and 2-frame synchronization channels per data frame at 10Mbps transmitting baud rate.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.8
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• pp.671-677
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• 2016

A Controller Area Network (CAN) is a serial communication protocol that is highly reliable and efficient in many aspects, such as wiring cost and space, system flexibility, and network maintenance. Therefore, it is chosen for the communication protocol between a single chip controller based on Field Programmable Gate Array (FPGA) and peripheral devices. In this paper, the design and implementation of CAN IP, which is written in VHSIC Hardware Description Language (VHDL), is presented. The implemented CAN IP is based on the CAN 2.0A specification. The CAN IP consists of three processes: clock generator, bit timing, and bit streaming. The clock generator process generates a time quantum clock. The bit timing process does synchronization, receives bits from the Rx port, and transmits bits to the Tx port. The bit streaming process generates a bit stream, which is made from a message received from a micro controller subsystem, receives a bit stream from the bit timing process, and handles errors depending on the state of the CAN node and CAN message fields. The implemented CAN IP is synthesized and downloaded into SmartFusion FPGA. Simulations using ModelSim and chip test results show that the implemented CAN IP conforms to the CAN 2.0A specification.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.2000-2003
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• 2002

In this paper, an IC chip of a cell- network type circuit constructed with 1-dimensional chaos circuits is reported. The circuit, is designed by sing switched-current (Sl) techniques. In the proposed circuit, by controlling connections of cells, an S- dimensional circuit (S ＝ 1, 2, 3,…) and a synchronization system can be constructed easily. Furthermore, in spite of faults of a few cells, the circuit can reconstruct above-mentioned systems only to change connections of cells. This feature will open up new vista for engineering applications which are used in a distance place such as space, deep sea, etc. since it is difficult to repair faults of these application systems. To investigate the characteristics of the circuit, SPICE simulations are performed. The VLSI chip is fabricated from the layout design using a CAD tool, MAGIC. The proposed circuit is integrable by a standard 1.2 $\mu\textrm{m}$ CMOS technology.

• Journal of Satellite, Information and Communications
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• v.5 no.1
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• pp.22-26
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• 2010

In this paper, we propose an effective method for detecting signals among multi-user in cooperative communication system. Spread sequence is inserted to NULL space of synchronization channel to synchronize between each user among frame formats of the cooperative communication and then transmitted. In the receiver, the wanted signal is detected by using correlation among the inserted spread sequences. As simulation results, correlations among the signals using Kasami/Walsh sequence in AWGN, Rician, and Rayleigh channel are shown. Using the simulation results in this paper, we expect a reliable cooperative communication.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.1
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• pp.53-58
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• 2008

A pellet program including a nested parallelism has a result of non-deterministic because of executed concurrently without synchronization. In order to detect like this error the visualization technique which is various is used. But the intuition characteristic is decreased because of limits of space and excessive abstraction. In this paper, proposes 3-D visualization engines which provide global structure of the arranging in a parallel program with nested parallelism which is complicated to the user. The visualization engine which is proposed provides global structure to the user as program easily to understand, it provides an effective debugging environment.

• Journal of Embryo Transfer
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• v.19 no.3
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• pp.191-199
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• 2004

This study was conducted to examine in vitro development of porcine embryos constructed by the microinjection of cultured fetal fibroblast cells into porcine oocytes matured in vitro. Single fetal donor cells were deposited into the perivitelline space of enucleated oocytes, followed by electrical fusion and activation. Activated embryos were cultured in NCSU-23 medium supplemented with 5％ FBS, at 38.5$^{\circ}C$ for 6 to 8 days in 5％ $CO_2$ and air. In experiment 1, fusion rates of nuclear transfer embryos did not differ for fetal fibroblast cells incubated in 5％ FBS + NCSU-23 or 5％ FBS + TL Heaps medium, nor did fusion rates of donor cells differ between 1-8 hr incubation durations. Fusion rates for the four treatment subclasses ranged from 72.1％ to 78.0％. In experiment 2, Pre-synchronization in medium containing 0.1 $\mu\textrm{g}$/m Hoechst 33342 an increase from 0 and 8 versus 15 h culture an increased percentage of porcine fibroblast cells in G2/M at the end of the synchronization period (12.4％, 17.5％ and 47.6％). Neither an increase in the concentration of H 33342 (0.2-1.6 $\mu\textrm{g}$/$m\ell$) nor a longer exposure time (12h, 18h and 24h) increased the proportion of porcine G2/M fibroblasts. In experiment 3, fusion rates did not differ significantly far nuclear transfer embryos constructed using donor cells cultured in 5％ FBS + NCSU-23 medium for 1-2, 6-8 or 12-14 days (60.0％, 73.3％ and 62.5％), respectively. The cleavage rate for nuclear transplant embryos using fetal fibroblast cells cultured for 1-2 days was 44.0％, significantly less than 56.7％ and 50.0％. for 6-8 or 12-14 days duration of culture, respectively. In experiment 4, the proportions of nuclear transfer embryos that developed to the $\geq$2 cell and to the blastocyst stage were not affected significantly by culture medium (5％ FBS + NCSU-23 or 5％ FBS + TL-Heaps) or by $O_2$ concentration of the culture (5％ vs 10％). Rates of development to the $\geq$2 cell stage ranged from 65.9％ to 70.1％, and development rates to the blastocyst stage ranged from 9.8％ to 12.5％ for the four treatment subclasses. Developmental rate was highest for embryos cultured in 5％ FBS + NCSU-23 under a gas atmosphere of 5％ $O_2$ in air.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.1
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• pp.61-67
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• 2011

The GPS new civil signal is modulated on the L2 carrier at a frequency of 1227.6MHz. The L2C signal is composed of two multiplexed code signals, which include CM code with a 10,230 chip sequency repeating every 20ms, and CL code which has a 767,250 chip sequency repeating every 1.5 seconds. Thus, the new civil signal have much improved cross correlation properties so that the position fixing can be possible even with very weak signals. However, it requires very long acquisition time because of its long code length. This paper presents an efficient signal acquisition method for L2C AGPS receiver. Snapshot mode and coarse time assistance are assumed and total integration time is given by 1.5 sec. By SNR worksheet and computer simulation, it is proven that L2C signal can be acquired with very weak power less than -150dBm. Considering the acquisition time and the sensitivity, it is recommended that the highest power signal is acquired with CM code first to reduce TTFF. By the timing synchronization, at this time, search space of the code phase for other signals can be greatly reduced so that CL code can be used in signal acquisition to maximize sensitivity with small computation.

• Journal of Digital Convergence
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• v.10 no.10
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• pp.289-294
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• 2012

In this paper, we take advantage of the characteristics of mobile smartphones can be serviced without the constraints of time and space, and Study was developed by a variety of mobile services were done in a traditional offline can be implemented in real-time Case Management Community. To this end, in addition to general PC/laptop, smart mobile until the configuration interface provide the same environment for HTML5 Web Switching and Optimal Network on the same device-specific browser Size to the implementation of the next generation of Web standards, HTML5-based integrated case management Web and Mobile Web. Hybrid App Development OS supports various kinds of smart devices based on SenchaTouch Mobile Framework between the server real-time synchronization and message through the implementation of the Push Notification function, administrators and guardians real-time two-way communication between the subjects is a real-time implementation of the system was implemented Case Management Community.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.12
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• pp.996-1001
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• 2005

Recently, with the development of service robots and with the new concept of ubiquitous world, the position estimation of mobile objects has been raised to an important problem. As pre-liminary research results, some of the localization schemes are introduced, which provide the relative location of the moving objects subjected to accumulated errors. To implement a real time localization system, a new absolute position estimation method for a mobile robot in indoor environment is proposed in this paper. Design and implementation of the localization system comes from the usage of active beacon systems (based upon RFID technology). The active beacon system is composed of an RFID receiver and an ultra-sonic transmitter: 1. The RFID receiver gets the synchronization signal from the mobile robot and 2. The ultra-sonic transmitter sends out the traveling signal to be used for measuring the distance. Position of a mobile robot in a three dimensional space can be calculated basically from the distance information from. Three beacons and the absolute position information of the beacons themselves. In some case, the mobile robot can get the ultrasonic signals from only one or two beacons, because of the obstacles located along the moving path. Therefore, in this paper, as one of our dedicated contribution, the position estimation scheme with less than three sensors has been developed. Also, the extended Kalman filter algorithm is applied for the improvement of position estimation accuracy of the mobile robot.