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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korea Institute of Information and Communication Engineering
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The Korean Institute of Information and Commucation Engineering
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Volume & Issues
Volume 13, Issue 12 - Dec 2009
Volume 13, Issue 11 - Nov 2009
Volume 13, Issue 10 - Oct 2009
Volume 13, Issue 9 - Sep 2009
Volume 13, Issue 8 - Aug 2009
Volume 13, Issue 7 - Jul 2009
Volume 13, Issue 6 - Jun 2009
Volume 13, Issue 5 - May 2009
Volume 13, Issue 4 - Apr 2009
Volume 13, Issue 3 - Mar 2009
Volume 13, Issue 2 - Feb 2009
Volume 13, Issue 1 - Jan 2009
Selecting the target year
SOM Matting for Alpha Estimation of Object in a Digital Image
Park, Hyun-Jun ; Cha, Eui-Young ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 1981~1986
This paper presents new matting techniques. The matting is an alpha estimation technique of object in an image. We can extract the object in an image naturally using the matting technique. The proposed algorithms begin by segmenting an image into three regions: definitely foreground, definitely background, and unknown. Then we estimate foreground, background, and alpha for all pixels in the unknown region. The proposed algorithms learn the definitely foreground and definitely background using self-organizing map(SOM), and estimate an alpha value of each pixel in the unknown region using SOM learning result. SOM matting is distinguished between global SOM matting and local SOM matting by learning method. Experiment results show the proposed algorithms can extract the object in an image.
A Study on Recognition of Both of New & Old Types of Vehicle Plate
Han, Kun-Young ; Woo, Young-Woon ; Han, Soo-Whan ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 1987~1996
Recently, the color of vehicle license plate has been changed from green to white. Thus the vehicle plate recognition system used for parking management systems, speed and signal violation detection systems should be robust to the both colors. This paper presents a vehicle license plate recognition system, which works on both of green and white plate at the same time. In the proposed system, the image of license plate is taken from a captured vehicle image by using morphological information. In the next, each character region in the license plate image is extracted based on the vertical and horizontal projection of plate image and the relative position of individual characters. Finally, for the recognition process of extracted characters, PCA(Principal Component Analysis) and LDA(Linear Discriminant Analysis) are sequentially utilized. In the experiment, vehicle license plates of both green background and white background captured under irregular illumination conditions have been tested, and the relatively high extraction and recognition rates are observed.
Musical Score Recognition Using Hierarchical ART2 Algorithm
Kim, Kwang-Baek ; Woo, Young-Woon ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 1997~2003
Methods for effective musical score recognition and efficient editing of musical scores are demanded because functions of computers for researches on musical activities become more and more important parts in recent days. In the conventional methods for handling musical scores manually, there are weak points such as incorrect score symbols in input process and requirement of much time to adjust the incorrect symbols. And also there is another weak point that the scores edited by each application program can be remodified by a specific application program only. In this paper, we proposed a method for automatic musical score recognition of printed musical scores in order to make up for the weak points. In the proposed method, staffs in a scanned score image are eliminated by horizontal histogram, noises are removed by 4 directional edge tracking algorithm, and then musical score symbols are extracted by using Grassfire algorithm. The extracted symbols are recognized by hierarchical ART2 algorithm. In order to evaluate the performance of the proposed method, we used 100 musical scores for experiment. In the experiment, we verified that the proposed method using hierarchical ART2 algorithm is efficient.
Design and Implementation of Location Based Seamless Handover for IEEE 802.11s Wireless Mesh Networks
Lee, Sung-Han ; Yang, Seung-Chur ; Kim, Jong-Deok ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2004~2010
The characteristic of the backbond for distribution service in WMNs(Wireless Mesh Networks) is that WMNs has multiple links connected to mesh points and dynamic routing protocol such as AODV to establish routing paths. When the terminal is communicating with the service through new AP, mobile nodes can resume communication by setting only the link between new AP and mobile node in the case of existing WLANs, but WMNs needs path establishment process in multihop networks. Our goal in this paper is to support the seamless communication service by eliminating path establishment delay in WMNs. We present the method that eliminates the handover latency by predicting the location of handover using GPS information and making the paths to their destination in advance. We implement mesh nodes using embedded board that contains proposed handover method and evaluate performance of handover latency. Our experiment shows that handover delay time is decreased from 2.47 to 0.05 seconds and data loss rate is decreased from 20~35% in the existing method to 0~10% level.
A Method of Improving Plan for The Local City Competitive Power Utilizing by Private Communication Networks in An Ubiquitous-City RFID Wireless Infra
Lee, Bong-Choon ; Ha, Deock-Ho ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2011~2018
The international society under the internet technology have been declining boundaries of the global economy. After this step, a social revolution will be happen from the ubiquitous technology which gives objects intelligence to serve people. And then it is expected that every part of a city competitive power is defined by both in quality and in quantity of the ubiquitous information unit in the future. On this score, now each nation is trying to set relative services and broadband networks to lead the ubiquitous industry. Therefore this paper analyzed about the progress and prospect of a local U-city plan in our nation. And than we propose a method of configurating broadband self-communication network on the base of cost and utilization Especially we propose a new city development model which use U-city and self-communication network to improve a city competitive power.
Survey on the Korean MCS Systems and Development Issues
Kim, Geon-Ung ; Park, Gyei-Kark ; Choi, Jo-Cheon ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2019~2029
There are several MCS(Monitoring, Control and Surveillance) systems for maritime safety and security in Korea; VMS (Vessel Monitoring System) that based on the AIS(Automatic Identification System), and the LRIT(Long-Range Identification and Tracking), the Vessel Free Pass System that based on the RFID(Radio Frequency IDentification), the Fisheries Information Network that provided by the National Federation of Fisheries Cooperatives. This paper surveys the fundamental technologies of MCS systems, and compares the role and function of them. It also surveys the development direction of each systems and research topics for cooperation of them.
The Effects on Social Welfare of Asymmetric Regulation in Mobile Telecommunications Termination Access Charge
Jung, Choong-Young ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2030~2038
We analyze the economic effects of mobile termination rate asymmetry by simulation model. The asymmetry allows the mobile operator to get access profits at the expense of the incumbent and induces negative effects such as the entry of inefficient operator and allocative efficiency as well as productive efficiency. We use simulation model to investigate the effect on social welfare of asymmetric regulation. If the brand loyalty is high, social welfare increase as the termination charge of entrant increases. The extension of the basic model shows that the degree of social welfare increase becomes higher as the brand loyalty increases when the cost of entrant is smaller than that of incumbent. But, the degree of social welfare decrease becomes lower as the substitution effects increase.
Design and fabrication of PSK carrier recovery circuit using multi-layer coupled line
Kim, Young-Wan ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2039~2044
The PSK carrier signal recovery circuit using multi-layer coupled line was analyzed and designed. The fabricated carrier recovery 6 port element with multi-layer coupled line structure gets the simple architecture. It is possible to implement the carrier signal recovery circuit of the same structure with the multi-layer six port phase correlator of the direct receiver front-end. Based on the analysis of RML carrier recovery circuit using the multi-layer coupled line 6-port phase correlator, the multi-layer coupled line carrier signal recovery structure for multi-mode coherent demodulation was proposed. The fabricated multi-layer coupled line carrier signal recovery circuit for quadrature phase shift-keying shows a good carrier signal characteristic with a constant phase and phase error below
A 5GHz-Band Low Noise Amplifier Using Depletion-type SOI MOSFET
Kim, Gue-Chol ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2045~2051
A 5-GHz band Low Noise Amplifier(LNA) using SOI MOSFET is designed. To improve the noise performance, depletion-type SOI MOSFET is adopted, and it is designed by the two-stage topology consisting of common-source and common-gate stages for low-voltage operation. The fabricated LNA achieved an S11 of less than -10dB, voltage gain of 21dB with a power consumption of 8.3mW at 5.5GHz, and a noise figure of 1.7dB indicated that the depletion-type LNA improved the noise figure by 0.3dB compared with conventional type. These results show the feasibility of a CMOS LNA employing depletion-type SOI MOSFET for low-noise application.
PCB Board Impedance Analysis Using Similarity Transform for Transmission Matrix
Suh, Young-Suk ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2052~2058
As the operating frequency of digital system increases and voltage swing decreases, an accurate and high speed analysis of PCB board becomes very important. Transmission matrix method, which use the multiple products of unit column matrix, is the highest speedy method in PCB board analysis. In this paper a new method to reduce the calculation time of PCB board impedances is proposed. First, in this method the eigenvalue and eigenvectors of the transmission matrix for unit column of PCB are calculated and the transmission matrix for the unit column is transformed using similarity transform to reduce the number of multiplication on the matrix elements. This method using the similarity transform can reduce the calculation time greatly comparing the previous method. The proposed method is applied to the 1.3 inch by 1.9 inch board and shows about 10 times reduction of calculation time. This method can be applied to the PCB design which needs a lots of repetitive calculation of board impedances.
Equivalent Admittance and Complex Powers in a Coupling through a Narrow Slit in a Parallel-Plate Waveguide
Lee, Jong-Ig ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2059~2065
In this study, it has been considered that the TEM wave is incident on the transverse slit in the upper plate of a short-ended parallel-plate waveguide (PPW). An equivalent slit admittance and complex power for the case of narrow slit are obtained. The conditions for the slit voltage and the complex power in case of the maximum coupling through the slit with a nearby scatterer exterior the PPW are checked.
-type Variable Attenuator with Low Phase Shift
Park, Ung-Hee ; Ahn, Gil-Cho ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2066~2070
A voltage controlled attenuator using a PIN diode and two resistors of the
-type fixed attenuator is described in this paper. The proposed variable attenuator operating for a fixed attenuation range has a good input VSWR and a low intermodulation signal. For the low phase shift, a PIN diode is connected with open stub for the purpose of phase compensation. The stub for phase compensation is calculated by the Deloach method and the related circuit theory. This attenuator is easily fabricated on the microstrip and can be normally used in fine control circuits within small attenuation range. The fabricated attenuator for 2110~2170 MHz frequency band has about 4 dB of an attenuation range,
of phase variance, and -20 dB of S11 according to the input voltage from 0 to 2.7 V.
Initial QP Determination Algorithm for Low Bit Rate Video Coding
Park, Sang-Hyun ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2071~2078
The first frame is encoded in intra mode which generates a larger number of bits. In addition, the first frame is used for the inter mode encoding of the following frames. Thus the intial QP (Quantization Parameter) for the first frame affects the first frame as well as the following frames. Traditionally, the initial QP is determined among four constant values only depending on the bpp. In the case of low bit rate video coding, the initial QP value is fixed to 35 regardless of the output bandwidth. Although this initialization scheme is simple, yet it is not accurate enough. An accurate intial QP prediction scheme should not only depends on bpp but also on the complexity of the video sequence and the output bandwidth. In the proposed scheme, we use a linear model because there is a linear inverse proportional relationship between the output bandwidth and the optimal intial QP. Model parameters of the model are determined depending on the spatial complexity of the first frame. It is shown by experimental results that the new algorithm can predict the optimal initial QP more accurately and generate the PSNR performance better than that of the existing JM algorithm.
A study on the development of the tabletop tiled display system and its application for high-resolution visualization
Park, Kyoung-Shin ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2079~2087
This paper describes the iTABLE tabletop tiled display system which is designed for displaying high-resolution scientific visualization. Unlike other tabletop systems that typically use a projection-based single display, iTABLE system is suitable for visualizing and sharing high-resolution data, and it is capable of facilitating group interaction with interactive data visualizations on a table and distributed collaborative visualizations with other tiled displays. First, it surveys prior works on tabletop and tiled display systems as well as scientific visualization, and it describes the design and implementation of iTABLE system, and middleware and an infrared camera-based tangible user interface designed for iTABLE system. It will then discuss some high-resolution scientific visualization applications developed for iTABLE followed by conclusions and future research directions.
Hybrid MAC Protocol Design for an Underwater Acoustic Network
Park, Jong-Won ; Ko, Hak-Lim ; Cho, A-Ra ; Yun, Chang-Ho ; Choi, Young-Chol ; Lim, Yong-Kon ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2088~2096
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.
Application Scenarios of Nautical Ad-hoc Network in Wireless Mobile Communication under Maritime Environment
Kim, Young-Bum ; Chang, Kyung-Hi ; Yun, Chang-Ho ; Park, Jong-Won ; Lim, Yong-Kon ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2097~2104
In terrestrial communications, high data rate transmission can be achieved by splitting the coverage area into small cells through base stations and reusing the resource efficiently. However, the geographical features of maritime communications require the long transmission range, and it is not practical to install base station on the sea to set up the similar deployment as the terrestrial communications, so MF/HF band modem with low data rate are currently utilized for maritime communications. And the expensive satellite communication via Inmarsat is the conventional solution for the high data rate transmission on the sea. To reduce the cost, Ad-hoc network is proposed to apply on the sea, which requires no base station for the peer-to-peer communications. In this paper, we denominate this maritime environment specific Ad-hoc network as Nautical Ad-hoc Network (NANET). Furthermore, the deployment scenario for the NANET, and the analysis on multiple access and duplexing schemes for the NANET are discussed in this paper, which serves as the cornerstone for the further NANET research and development.
RFID Tag Identification with Scalability Using SP-Division Algorithm on the Grid Environment
Shin, Myeong-Sook ; Ahn, Seong-Soo ; Lee, Joon ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2105~2112
Recently RFID system has been adopted in various fields rapidly. However, we ought to solve the problem of privacy invasion that can be occurred by obtaining information of RFID Tag without any permission for popularization of RFID system To solve the problems, it is Ohkubo et al.'s Hash-Chain Scheme which is the safest method. However, this method has a problem that requesting lots of computing process because of increasing numbers of Tag. Therefore, We suggest the way (process) satisfied with all necessary security of Privacy Protection Shreme and decreased in Tag Identification Time in this paper. First, We'll suggest the SP-Division Algorithm seperating SPs using the Performance Measurement consequence of each node after framing the program to create Hash-Chain Calculated table to get optimized performance because of character of the grid environment comprised of heterogeneous system. If we compare consequence fixed the number of nodes to 4 with a single node, equal partition, and SP partition, when the total number of SPs is 1000, 40%, 49%, when the total number of SPs is 2000, 42%, 51%, when the total number of SPs is 3000, 39%, 49%, and when the total number of SPs is 4000, 46%, 56% is improved.
OTP Authentication Protocol Using Stream Cipher with Clock-Counter
Cho, Sang-Il ; Lee, Hoon-Jae ; Lee, Sang-Gon ; Lim, Hyo-Taek ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2113~2120
User authentication has been one of the most important part of the network system. OTP(One-Time Password) has been developed and applied to the existing authentication system. OTP makes a different password and abrogates used password each time when user is authenticated by the server. Those systems prevent stolen-key-problems which is caused by using the same key every log-in trial. Yet, OTP still has vulnerabilities. In this paper, an advanced protocol which is using clock-count method to apply a stream cipher algorithm to OTP protocols and to solve problems of existing OTP protocols is proposed.
The Risk of Wardriving Attack Against Wireless LAN and its Counterplan
Choi, Young-Nam ; Cho, Sung-Mok ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2121~2128
The application range of IEEE 802.11 wireless LAN has rapidly expanding from campus, enterprise to the public network of Hot Spot area due to the advantages of easiness of construction, mobility of wireless client station, convenience of usage and so on. However the security of WLAN(Wireless LAN) is vulnerable inherently because of using RF as a medium, and so the dangers of infringement of personal information and inside data of enterprises have increased and wardriving attack searching for security vulnerability in wireless LAN has become more serious especially. In this paper, we find out the overview of various procedures and preparatory stages for wardriving attack against wireless LAN, and propose complementary methods to prevent information infringement accidents from wardriving attack in wireless LAN. For this purpose, we make an equipment which is suitable for wardriving in wireless LAN and show security vulnerability of AP(Access Point) operation in WLAN around Yangjae-Dong in Seoul as a result of using the equipment.
Fault Diagnosis in the CA Analyzer and Fault Detection of the Input Sequence
Cho, Sung-Jin ; Kwon, Min-Jeong ; Yim, Ji-Mi ; Kim, Jin-Gyoung ; Park, Young-Gyu ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2129~2139
In this paper, we diagnose the fault in the CA analyzer by setting up the initial value such that the final test signature is a constant regardless of the circuit being tested. This method makes the CA test procedure short and clear. In addition, we detect the fault of the faulty input sequence by using the inverse matrix of the CA state transition matrix.
The Proximity Scheme of the Perceptual Space for Indexing The Trajectories of Tags
Kim, Dong-Hyun ; Ahn, Swng-Woo ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2140~2146
Since tags do not have location informations, the identifiers of tags which are symbolic data are used as the location informations. Therefore, it is difficult to define the proxmity between two trajectories of tags and inefficient to process the user queries for tags. In this paper, we define the perceptual space to model the location of a tag and propose the proximity of the perceptual spaces. The proximity of the perceptual spaces is composed of the static proximity and dynamic proximity. Using the proximity of the perceptual spaces, it is possible to measure the proximity between two trajectories of tags and build the efficient indexes for tag trajectories. We evaluated the performance of the proposed proximity function for tag trajectories on the IR-tree and the
A design of hybrid type linear motor and measurement of the thrust force characteristics
Kim, Moon-Hwan ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2147~2153
A Hybrid type Linear Pulse Motor(LPM) for low cost is designed as single side stator structure. The static and dynamic characteristics measurement systems are designed. Experimental measurement systems, which measure the static and dynamic characteristic of the LPM, are uggested for the prototype LPM. It becomes known the values of the thrust forces. Finally the microstep drive method is adopted to the drive of prototype LPM. The waveform difference is measured between the microstep method and rectangular wave. From the experimental results, it can be confirmed that the repetitive ripple of the thrust force of the prototype LPM are reduced by taking the microstep drive method.
) Scalar Multiplier for Elliptic Curve Cryptography for Smartcard Security
Jeong, Sang-Hyeok ; Shin, Kyung-Wook ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2154~2162
This paper describes a scalar multiplier for Elliptic curve cryptography for smart card security. The scaler multiplier has 163-bits key size which supports the specifications of smart card standard. To reduce the computational complexity of scala multiplication on finite field, the non-adjacent format (NAF) conversion algorithm which is based on complementary recoding is adopted. The scalar multiplier core synthesized with a 0.35-
CMOS cell library has 32,768 gates and can operate up to 150-MHz@3.3-V. It can be used in hardware design of Elliptic curve cryptography processor for smartcard security.
Image Segmentation of Lung Parenchyma using Improved Deformable Model on Chest Computed Tomography
Kim, Chang-Soo ; Choi, Seok-Yoon ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2163~2170
We present an automated, energy minimized-based method for Lung parenchyma segmenting Chest Computed Tomography(CT) datasets. Deformable model is used for energy minimized segmentation. Quantitative knowledge including expected volume, shape of Chest CT provides more feature constrain to diagnosis or surgery operation planning. Segmentation subdivides an lung image into its consistent regions or objects. Depends on energy-minimizing, the level detail image of subdivision is carried. Segmentation should stop when the objects or region of interest in an application have been detected. The deformable model that has attracted the most attention to date is popularly known as snakes. Snakes or deformable contour models represent a special case of the general multidimensional deformable model theory. This is used extensively in computer vision and image processing applications, particularly to locate object boundaries, in the mean time a new type of external force for deformable models, called gradient vector flow(GVF) was introduced by Xu. Our proposed algorithm of deformable model is new external energy of GVF for exact segmentation. In this paper, Clinical material for experiments shows better results of proposal algorithm in Lung parenchyma segmentation on Chest CT.
A Novel Image Encryption using MLCA and CAT
Piao, Yong-Ri ; Cho, Sung-Jin ; Kim, Seok-Tae ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2171~2179
In this paper, we propose a novel Image Encryption using MLCA (Maximum Length Cellular Automata) and CAT (Cellular Automata Transform). Firstly, we use the Wolfram rule matrix to generate MLCA state transition matrix T. Then the state transition matrix T changes pixel value of original image according to pixel position. Next, we obtain Gateway Values to generate 2D CAT basis function. Lastly, the basis function encrypts the MLCA encrypted image into cellular automata space. The experimental results and security analysis show that the proposed method guarantees better security and non-lossy encryption.
Real-time Hand Gesture Recognition System based on Vision for Intelligent Robot Control
Yang, Tae-Kyu ; Seo, Yong-Ho ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2180~2188
This paper is study on real-time hand gesture recognition system based on vision for intelligent robot control. We are proposed a recognition system using PCA and BP algorithm. Recognition of hand gestures consists of two steps which are preprocessing step using PCA algorithm and classification step using BP algorithm. The PCA algorithm is a technique used to reduce multidimensional data sets to lower dimensions for effective analysis. In our simulation, the PCA is applied to calculate feature projection vectors for the image of a given hand. The BP algorithm is capable of doing parallel distributed processing and expedite processing since it take parallel structure. The BP algorithm recognized in real time hand gestures by self learning of trained eigen hand gesture. The proposed PCA and BP algorithm show improvement on the recognition compared to PCA algorithm.
Optoelectronic Mixing Detection for the Extension of Useable Frequency Range in the Radio over Fiber Network
Choi, Young-Kyu ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2189~2196
Theoretical analysis is presented for expending of the usable frequency range of optoelectronic mixing detection in the radio over fiber network system. We define the normalized gain to evaluate the performance of the optical mixing detection, and conform the possibilities of detection for the high frequency signals beyond the cutoff frequency of a photodiode. Optical mixing detection mechanism is analyzed by solving the continuity equation for the carriers of a photodiode. The normalized gain is independent on the signal frequency and the frequency difference between the optical signal and the local signal. Also, the amplitude of the local signal and the bias voltage are needed to be optimized at the same time in order to maximize the normalized gain.
Signal Detection with Sphere Decoding Algorithm at MIMO Channel
An, Jin-Young ; Kang, Yun-Jeong ; Kim, Sang-Choon ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2197~2204
In this paper, we analyze the performance of the sphere decoding algorithm at MIMO system. The BER performance of this algorithm is the same as that of ML receiver, but computational complexity of SD algorithm is much less than that of ML receiver. The independent signals from each transmit antennas are modulated by using the QPSK and 16QAM modulation in the richly scattered Rayleigh flat-fading channel. The received signals from each receivers is independently detected by the receiver using Fincke & Pohst SD algorithm, and the BER output of the algorithm is compared with those of ZF, MMSE, SIC, and ML receivers. We also investigate the Viterbo & Boutros SD algorithm which is the modified SD algorithm, and the BER performance and the floting point operations of the algorithms are comparatively studied.
Detection of Inflection Point of Waveform by Wavelet Threshold Denoising
Kim, Tae-Soo ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2205~2210
In this paper, the proposed method is a denoising technology by tangent curve interpolation of zero points. The problem of the hard threshold method is improved by the proposed method. The quantity of time fluctuation of the electromagnetic signal as the quantity of electric fluctuation of the natural world or the curve of motion waveform of the fast movement of human extracted using virtual reality is, in fact, complex. Therefore it is important to decide exactly the signal properties as the inflection point for observation signal. In particular, it is necessary to extract the properties after denoising, since the measurement signal of the natural world include some noises. It shows that the noise of the inflection point signal with noise II, noise factor 5, is eliminated by the proposed method, and the result of SNR for the signal is improved 3.4dB than that by the conventional hard threshold.
Performance Enhancement of Speech Communication System using Reverberation Rejection
Kim, Se-Young ; Kang, Suk-Youb ; Kim, Ki-Man ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2211~2217
In this paper, we propose the speech enhancement algorithm using an one-microphone in a reverberant room environments. Spectral subtraction is the effective method which can reduce the reverberation element and the noise in a spectrum domain. Spectral subtraction needs correct separation of voice section and silent section therefore to improve the performance, voice activity detection(VAD) based on entropy has been applied to the proposed method. We test a performance of the proposed method by comparing with conventional method which used VAD based on energy detection. Reverberation reduction ratio with variable of SNR and a reverberation time is used as a test index. From the simulation result, proposed method shows performance better than conventional method.
Improved MAC Protocol Synchronization Algorithm using Compensating value in Wireless Mesh Networks
Yun, Sang-Man ; Lee, Soon-Sik ; Lee, Sang-Wook ; Jeon, Seong-Geun ; Lee, Woo-Jae ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2218~2226
TDMA based MAC protocol supporting wireless mesh network has many advantage rather than 802.11 DCF/EDCA protocol based on packet. But TDMA based MAC protocol require new synchronization method because of mobile point oscillator's difference, and distributed environments. This thesis propose synchronization method for TDMA based MAC protocol. It divides MP(Mobile Points) states into 4 types. If MP is in sync mode, it schedules TDMA local start time in time skew interval using beacon. It proposes compensation algorithms to compensate time skew caused by clock drift. This proposal show that general time error and clock drift rate value reduced and get synchronized result.
A New Upper Layer Decoding Algorithm for MPE-FEC based on LLR
Kim, Chul-Seung ; Kim, Min-Hyuk ; Park, Tae-Doo ; Kim, Nam-Soo ; Jung, Ji-Won ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2227~2234
DVB-SSP is a new broadcasting system for hybrid satellite communications, which supports mobile handheld systems and fixed terrestrial systems. An upper layer, including erasure Reed-Solomon error correction combined with cyclic redundancy check. However, a critical factor must be considered in upper layer decoding. If there is only one bit error in an IP packet, the entire IP packet is considered as unreliable bytes, even if it contains correct bytes. If, for example, there is one real byte error, in an IP packet of 512 bytes, 511 correct bytes are erased from the frame. Therefore, this paper proposed upper layer decoding methods; LLR-based decoding. By means of simulation we show that the performance of the proposed decoding algorithm is superior to that of the conventional one.
A study for implementation of wireless sensor network to optimize building environment
Chung, Sung-Boo ; Kim, Joo-Woong ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2235~2241
RFID and USN are major technology in Ubiquitous. RFID is an automatic identification method, relying on storing and remotely retrieving data using devices called RFID tags or transponders through RFID reader. USN is wireless sense network and monitoring environment conditions that is temperature, noise, pressure, oscillation. In this paper, we propose wireless sensor network system that is monitoring to optimize environment conditions.
Application Development and Performance Analysis of Smartphone-based QR Code Interpreter
Park, Chan-Jung ; Hyun, Jung-Suk ;
Journal of the Korea Institute of Information and Communication Engineering, volume 13, issue 10, 2009, Pages 2242~2250
Recently, with the advance of Ubiquitous era, the types of services become diverse. Especially, due to the rapid development of mobile technology, the new functions of mobile phones are added and the new applications of mobile phones are developed actively. Among the various applications related to mobile phones, 2 dimensional barcode-based applications are increasing. 2 dimensional barcode is mostly used for the management of past record. However, by combing 2 dimensional barcode with mobile phones, the application areas of 2 dimensional barcode are expanded to the means of publicity for education, tourism, and festivals. In this paper, we develop a QR code decoder running on smartphones, which connects on-line and off-line. In addition, we modify our decoder by detecting the point for performance enhancement based on TRIZ. We compare our decoder with an open-source based decoder in terms of the code size of decoding and the speed of decoding in order to prove that our decoder has a better performance than the other. Finally, we introduce two applications: u-map and u-pamphlet as QR code applications.