• Proceedings of the KIEE Conference
• /
• 1999.07g
• /
• pp.3239-3241
• /
• 1999

Two-dimensional optical code-division multiple access is a system to transmit a two- dimensional data via parallel transmission line. The probability density function (pdf) of interference noise from other users is calculated and the pdf of asynchronous interference noise is newly calculated to present lower bounds of probability of error. The corresponding bit error rate is evaluated from this results.

• Journal of the Optical Society of Korea
• /
• v.15 no.1
• /
• pp.103-108
• /
• 2011

Recently reported asynchronous-optical-sampling terahertz (THz) time-domain spectroscopy enables high-resolution spectroscopy due to a long time-delay window. However, a long-lasting tail signal following the main pulse is often measured in a time-domain waveform, resulting in spectral fluctuation above a background noise level on a high-resolution THz amplitude spectrum. Here, we adopt the wavelet power spectrum estimation technique (WPSET) to effectively remove the spectral fluctuation without sacrificing spectral features. Effectiveness of the WPSET is verified by investigating a transmission spectrum of water vapor.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.9
• /
• pp.1915-1922
• /
• 2012

In this paper, the Solar Inverter will be monitored by using the AJAX(Asynchronous JavaScript and XML). AJAX is the one of the technologies that can make the RIA(Rich Internet Application) with DHTML(Dynamic Hyper Text Makeup Language) and other java script technology. By using this, a strong application program that is comparable to the general application program can be made. With an existing data-processing technique, the request and response of data can't be processed dynamically on the same page. However, real-time monitoring of data and operation statuses can be confirmed by using the AJAX an asynchronous method of communication. Also without changing the page, the amount of data transmission used the AJAX with significantly small amounts of data to build a Solar Inverter monitoring system that is able to efficiently handle management and monitoring, operating all functions within one page.

• International Journal of Control, Automation, and Systems
• /
• v.3 no.4
• /
• pp.533-541
• /
• 2005

In this paper, a wind turbine with power splitting transmission, which is realized through a novel three-shaft planetary, is presented. The input shaft of the transmission is driven by the rotor of the wind turbine, the output shaft is connected to the grid via the main generator (asynchronous generator), and the third shaft is driven by a control motor with variable speed. The dynamic models of the sub systems of this wind turbine, e.g. the rotor aerodynamics, the drive train dynamics and the power generation unit dynamics, were given and linearized at an operating point. These sub models were integrated in a multidisciplinary dynamic model, which is suitable for control syntheses to optimize the utilization of wind energy and to reduce the excessive dynamic loads. The important dynamic behaviours were investigated and a wind turbine with a soft main shaft was recommend.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.8
• /
• pp.31-37
• /
• 2016

Ranging is divided into a synchronous scheme and an asynchronous scheme according to the presence of global synchronization between nodes. In general, the asynchronous ranging is preferred over synchronous ranging because it does not require an expensive high-precision oscillator for the global synchronization. On the other hand, in a conventional asynchronous ranging scheme, the packets, which are generated by all nodes in a positioning system of a large-scale infrastructure and need to be sent for localization by reference nodes, are considerable, which cause an increase in network traffic as the number of nodes increases. The traffic congestion lowers the throughput of the network leading to a considerable loss of energy. To solve this problem, this paper proposes a ranging scheme, in which virtual transmission slots randomly and discretely selected by a plurality of nodes are used to reduce the overheads needed in synchronizing the nodes, and the ranging is performed asynchronously based on the virtual transmission slots, thereby decreasing the network traffic. In addition, a performance test proved that the proposed ranging scheme was stronger than the TWR and SDS-TWR on an error range, even though the intensity of traffic was very low.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.47 no.1
• /
• pp.28-37
• /
• 2010

In this paper, the IC (Integrated Circuit) for multi-channel asynchronous communication was designed by using FPGA and VHDL language. The existing chips for asynchronous communication that has been used commercially are composed of one to two channels. Therefore, when communication system with two channels or more is made, the cost becomes high and it becomes complicated for communication system to be realized and also has very little buffer, load that is placed into Microprocessor increases heavily in case of high speed communication or transmission of high-capacity data. The designed IC was improved the function and performance of communication system and reduced costs by designing 8 asynchronous communication channels with only one IC, and it has the size of transmitter/receiver buffer with 256 bytes respectively and consequently high speed communication became possible. To detect errors between communications, it was designed with digital filter and check-sum logic and channel MUX logic so that the malfunction can be prevented and errors can be detected more easily and input/output port regarding each communication channel can be used flexibly and consequently the reliability of system was improved. It was composed and simulated logic of VHDL described by using Cyclone II Series EP2C35F672C8 and QuartusII V8.1 of ALTERA company. In order to show the performance of designed IC, the test was conducted successfully in QuartusII simulation and experiment and the excellency was compared with TL16C550A of TI (Texas Instrument) company and ATmegal28 general-purpose micro controller of ATMEL company that are used widely as chips for asynchronous communication.

• Journal of the Korea Society of Computer and Information
• /
• v.3 no.3
• /
• pp.83-87
• /
• 1998

This paper presents a security and authentification scheme against unauthorized disclose and attack in ATM(Asynchronous Transmission Method) with various service. Four various options to place security layer between the AAL and ATM layers is discussed. The suggested security and authentification can be integrated with the call setup procedures of ATM.

• Proceedings of the IEEK Conference
• /
• 1999.06a
• /
• pp.9-12
• /
• 1999

The 6Bone is an environment supporting experimentation with the IPv6 protocols and products implementing it. Several functions of IPv6 remain loosely defined or undefined but the protocols related on IPv6 are being developed continuously. It is clear that ATM(Asynchronous Transfer Mode) technology is playing a important role in the evolution of the Internet as a transmission medium. In this paper, we suggest a design plan for the 6Bone overlayed on the existing ATM network, KOREN(Korea Research and Education Network). The planed 6Bone will become a good testbed to develop new networking technology and new services related on IPv6.

• Proceedings of the KIEE Conference
• /
• 2007.04a
• /
• pp.264-266
• /
• 2007

Orthogonal Variable Spreading Factor codes are used as channelization codes in WCDMA. In this particular paper, we present a new OVSF codes which is generated from the Jacket Matrices for DS-CDMA systems. The simulations result shows that the purposed OVSF can efficiently reduce the peak values of the correlations than the conventional HOVSF without orthogonality loss. It will be useful to detect the multi-user system under the asynchronous system and save the power of transmission.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.22 no.51
• /
• pp.99-108
• /
• 1999

B-ISDN link dimensioning is often known as a difficult problem because of the characteristics of Asynchronous Transfer Mode(ATM) such as various Quality of Services of different service requirements, and the statistical multiplexing resulting from virtual path/virtual circuit connections. In this paper, we propose a nonlinear integer optimization model for dimensioning B-ISDN considering the statistical multiplexing effects of virtual path connections(VPCs) and the modularity of resources allocated to a transmission link. The algorithm based on the simultaneous linear approximation technique as well as some numerical results will be also presented.