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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Journal of Korean Institute of Communications and Information Sciences
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The Korean Institute of Communications and Information Sciences
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Volume & Issues
Volume 40, Issue 12 - Dec 2015
Volume 40, Issue 11 - Nov 2015
Volume 40, Issue 10 - Oct 2015
Volume 40, Issue 9 - Sep 2015
Volume 40, Issue 8 - Aug 2015
Volume 40, Issue 7 - Jul 2015
Volume 40, Issue 6 - Jun 2015
Volume 40, Issue 5 - May 2015
Volume 40, Issue 4 - Apr 2015
Volume 40, Issue 3 - Mar 2015
Volume 40, Issue 2 - Feb 2015
Volume 40, Issue 1 - Jan 2015
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Efficient Calculation for Decision Feedback Algorithms Based on Zero-Error Probability Criterion
Kim, Namyong ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 247~252
DOI : 10.7840/kics.2015.40.2.247
Adaptive algorithms based on the criterion of zero-error probability (ZEP) have robustness to impulsive noise and their decision feedback (DF) versions are known to compensate effectively for severe multipath channel distortions. However the ZEP-DF algorithm computes several summation operations at each iteration time for each filter section and this plays an obstacle role in practical implementation. In this paper, the ZEP-DF with recursive gradient estimation (RGE) method is proposed and shown to reduce the computational burden of O(N) to a constant which is independent of the sample size N. Also the weight update of the initial state and the steady state is a continuous process without bringing about any propagation of gradient estimation error in DF structure.
A Threshold Optimization Method for Decentralized Cooperative Spectrum Sensing in Cognitive Radio Networks
Kim, Nak-Kyun ; Byun, Youn-Shik ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 253~263
DOI : 10.7840/kics.2015.40.2.253
Lately, spectrum sensing performance has been improved by using cooperate spectrum sensing which each results of sensing of several secondary users are reported to the fusion center. Using Cognitive Radio, secondary user is able to share a bandwidth allocated to primary user. In this paper, we propose a new decentralized cooperative spectrum sensing scheme which compensates the performance degradation of existing decentralized cooperative spectrum sensing considering the error probability of the channel which sensed result of the secondary user is delivered to the fusion center in decentralized cooperative spectrum sensing. In addition, a sensing threshold optimization of minimizing the error probability of decentralized cooperative spectrum sensing is introduced by deriving the equation and the optimal sensing threshold has been confirmed to maximize the decentralized cooperative spectrum sensing performance.
Correlation Property of Encrypted Spreading Code for Design of LPI Applied GNSS Signal
Park, Ki-Hyeon ; Song, Min Kyu ; Song, Hong-Yeop ; Lee, Jang-Yong ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 264~272
DOI : 10.7840/kics.2015.40.2.264
In this paper, we analyze the statistical characteristic and describe the anti-interference performance of the signal for the LPI-applied GNSS using encrypted spreading code. To do this, we analyze the correlation property of encrypted sequences theoretically having various symbol sets over complex root of unity. We derive the degradation of anti-interference performance of encrypted sequences comparing with Gold and Zadoff-Chu sequences using theoretical and experimental methods.
Feasibility of Interference Alignment for Reverse Duplex in MIMO Cellular Networks with One-side Base Cooperation
Kim, Kiyeon ; Jeon, Sang-Woon ; Yang, Janghoon ; Kim, Dong Ku ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 273~284
DOI : 10.7840/kics.2015.40.2.273
The feasibility conditions of interference alignment (IA) are analyzed for reverse duplex systems, in which one cell operates as downlink (DL) while the other cell operates as uplink (UL) assuming one-sid base station (BS) cooperation. Under general multiple-input and multiple-output (MIMO) antenna configurations, a necessary condition and a sufficient condition for one-shot linear IA are established, i.e., linear IA without symbol or time extension. In several example networks, optimal sum degrees of freedom (DoF) is characterized by the derived necessary condition and sufficient condition. For some special class of networks, a sufficient condition is established in a more compact expression, which also yields the necessary and sufficient condition. Simulation results demonstrate that the proposed IA does not only achieve larger DoF but also significantly improves the sum rate in the practical signal-to-noise ratio (SNR) regime.
Ultra-WideBand Channel Measurement with Compressive Sampling for Indoor Localization
Kim, Sujin ; Myung, Jungho ; Kang, Joonhyuk ; Sung, Tae-Kyung ; Lee, Kwang-Eog ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 285~297
DOI : 10.7840/kics.2015.40.2.285
In this paper, Ulta-WideBand (UWB) channel measurement and modeling based on compressive sampling (CS) are proposed. The sparsity of the channel impulse response (CIR) of the UWB signal in frequency domain enables the proposed channel measurement to have a low-complexity and to provide a comparable performance compared with the existing approaches especially used for the indoor geo-localization purpose. Furthermore, to improve the performance under noisy situation, the soft thresholding method is also investigated in solving the optimization problem for signal recovery of CS. Via numerical results, the proposed channel measurement and modeling are evaluated with the real measured data in terms of location estimation error, bandwidth, and compression ratio for indoor geo-localization using UWB system.
An Efficient Resource Allocation Scheme For An Integrated Satellite/Terrestrial Networks
Park, Unhee ; Kim, Hee Wook ; Oh, Dae-Sub ; Jang, Dae-Ik ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 298~306
DOI : 10.7840/kics.2015.40.2.298
In this paper, we propose an efficient resource allocation scheme for the integrated satellite/terrestrial networks. The proposed scheme is a frequency sharing technique to mitigate the inter-component interferences which can be generated between a satellite beam and terrestrial cells that are operated in the same frequency. The proposed dynamic resource allocation scheme can mitigate the total inter-component interference by optimizing the total transmission power and it can expect a result of which can lead to an increase in capacity. In such a system, the interference situation can be affected by the distributed traffic demands or up/down link communications environments. In this point of view, we evaluate the performance of the total consumed power, the amount of inter-component interference with respect to different traffic distributions and interference environments between the satellite beam and terrestrial systems.
DFT-Based Channel Estimation Scheme for the Uplink of LTE-A Systems
Kim, Kyung Jun ; Choi, Kyung Jun ; Kim, Kwang Soon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 307~309
DOI : 10.7840/kics.2015.40.2.307
In this letter, a DFT-based channel estimator is proposed for the uplink of LTE-A systems to solve the leakage and enhance the spectral efficiency. It is confirmed that the proposed estimator can significantly improve user and cell spectral efficiencies compared to conventional estimators.
Square-Law Combining-Aided SIM/SM for Optical Wireless Communication
Lee, Jeong-Ho ; Hwang, Seung-Hoon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 310~312
DOI : 10.7840/kics.2015.40.2.310
In this paper, we propose an SIM/SM system with a square-law combining. In an outdoor environment, the performance of SIM/SM deteriorates due to an atmospheric turbulence. The square-law combining technique can enhance the performance of the SIM/SM by employing square-and-integrate operation at the receiver side. For various spectral efficiencies, the performance gain increases as the number of photodetectors increases. Furthermore, as the turbulence strength increases, the performance gain also increases.
Heterogeneous Interface Decision Engine and Architecture for Constructing Low Power Home Networks
Bae, Puleum ; Jo, Yeong-Myeong ; Moon, Eui-Kyum ; Ko, Young-Bae ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 313~324
DOI : 10.7840/kics.2015.40.2.313
In this paper, in order to support the construction of a smart home environment of low power consumption, we propose a heterogeneous interface determination engine and architecture. Technology of "smart home" is in the spotlight according to the development of IT technology nowadays. Smart homes are configured with multiple sub-networks, and each sub-network is formed by the smart devices using various communication interfaces. Thus, in the smart home environment, interlocking technology between heterogeneous interfaces is essentially required for supporting communication between different networks. Further, each communication interface is a difference in power consumption, and home smart devices are often operated in 24 hours, especially smart phones and other wireless devices are sensitive to power consumption. Therefore, in order to build a energy efficient home network, It is important to select the appropriate interface to handle traffic depending on the situation. In this paper, we propose "The Heterogeneous Interface Decision Engine and Architecture for constructing of Low Power Home Network," and analyze the performance of the proposed method and verify the validity through experiments on the test bed.
The Effects of Optical Cable Fault on Customer Complaints
Jung, So-Ki ; Cha, Kyoung Cheon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 325~333
DOI : 10.7840/kics.2015.40.2.325
In this paper, we are aim to analysis the effects of optical cable fault on customer complaints. We considered several causes: the elapse time to allow repair from the optical cable fault, whether working day or not, seasonality and human error, external construction, optical cable cutting or core banding that is controllable causes and natural disasters, vehicle crash, fire that is uncontrollable causes. The results of analysis are as follows: First, customer complaints increase through indifferencial relationship when using the production function for the number of expected victims and elapsed time due to the optical cable fault. Second, not only the elapsed time but also controllable variables, human error, external construction, the core cut occurs, increased customer complaints due to optical cable faults.
Evil-Twin Detection Scheme Using SVM with Multi-Factors
Kang, SungBae ; Nyang, DaeHun ; Lee, KyungHee ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 334~348
DOI : 10.7840/kics.2015.40.2.334
Widespread use of smart devices accompanies increase of use of access point (AP), which enables the connection to the wireless network. If the appropriate security is not served when a user tries to connect the wireless network through an AP, various security problems can arise due to the rogue APs. In this paper, we are going to examine the threat by evil-twin, which is a kind of rogue APs. Most of recent researches for detecting rogue APs utilize the measured time difference, such as round trip time (RTT), between the evil-twin and authorized APs. These methods, however, suffer from the low detection rate in the network congestion. Due to these reasons, in this paper, we suggest a new factor, packet inter-arrival time (PIAT), in order to detect evil-twins. By using both RTT and PIAT as the learning factors for the support vector machine (SVM), we determine the non-linear metric to classify evil-twins and authorized APs. As a result, we can detect evil-twins with the probability of up to 96.5% and at least 89.75% even when the network is congested.
Magnetic Signals Analysis for Vehicle Detection Sensor and Magnetic Field Shape
Choi, Hak-Yun ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 349~354
DOI : 10.7840/kics.2015.40.2.349
This paper is about utilizing magnetic sensor to measure magnetic signal and analyze the form of magnetic signal for vehicle detection. For magnetic sensor, MR sensor from Honeywell company was used, and Helmholtz coil of which 3 axis' length is 1.2 m was manufactured to check the capability of the sensor and estimate its ability to detect the magnetic field. Vehicle detection was performed in following steps: installing sensor in road lane and non-road lane; estimating magnetic field when the vehicle is run by the driver; and estimating magnetic field of 7 different vehicles with different sizes. Also, sensor was installed at SUV and small-sized vehicle's park and non-park area to analyze the form of magnetic field. Lastly, the form of magnetic field made by different parts of the vehicle was analyzed. Based on the analysis, the form of magnetic field's magnetic peak value was bigger for road lane than non-road lane, complicated form was useful to distinguish the road lane above the installed sensor and the location of the running car, and the types of vehicle could be sorted because the variance of the magnetic field was bigger for bigger size of the vehicle. Also, it was confirmed that the forms of vehicle in parts-by-parts estimates.
3-Port Circulator for X-Band Radar
Yoon, Sung-Hyun ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 355~362
DOI : 10.7840/kics.2015.40.2.355
In this study, we have fabricated 9.385[GHz] circulator that is composed of WR112 waveguide and Ferrite for X-band radar. For designing Ferrite, B/R mode(Below Resonance mode) was used and calculated the condition of 120 degree rotation of the electric field in Ferrite and calculated internal DC magnetic field and external DC magnetic field. Also, dielectric materials of the same shape with Ferrite was filled between two Ferrite for improving the performance of the circulator, including impedance matching, bandwidth, quality factor, insertion loss. To obtain optimum shape of the Ferrite and dielectric material, we used CST MWS. Simulation result of the circulator is that 1.02 : 1 VSWR, -40dB isolation, 0.2dB insertion loss and measurement result is that 1.03 : 1, -38dB, 1.2dB at 9.385[GHz]. We can get good agreement at isolation and VSWR, but insertion loss was 1 dB great than simulation result.
Implementation of Mirroring and Efficient User Interface System for Smart Phone
Kim, Jeong-Hoon ; Ko, Do-Young ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 363~365
DOI : 10.7840/kics.2015.40.2.363
Recently, Smart Phone is widely used and replaces with the work of computer system. So, to overcome the inconveniences of Smart-Phone small screen size, a mirroring the screen of Smart Phone to TV or Computer monitor is studied to show a larger screen to the users. In this study, we implemented a screen mirroring and efficient user interface(computer mouse and keyboard) system with Bluetooth and USB host functions for a smart phone using standard 5 pin(MHL compatible) connector output to HDMI Monitor. Dock-style and Monitor embedded system are designed respectively.
MAC Layer Protocol for Improvement in Power Consumption and Time Delay in a Sensor Network
Shin, Jae Kwan ; Park, Dong Chan ; Kim, Suk Chan ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 366~368
DOI : 10.7840/kics.2015.40.2.366
This paper proposes a MAC protocol for sensor networks such as disaster detection system which generate the non-periodic packet. B-MAC has been used to solve delay problem for sensor networks, however, the power loss occurs due to excessive preamble and over-hearing. In contrast, S-MAC has a number of drawbacks in power consumption due to synchronization. In this paper, we propose H-MAC and analyze its performance which has improved power consumption compared to S-MAC and overhead and over-hearing compared to B-MAC.
SNR-Based Selective Relaying Scheme in Wireless Networks
Ju, MinChul ; Kwon, Tai-Gil ; Cho, Jin-Woong ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 369~371
DOI : 10.7840/kics.2015.40.2.369
In this letter, we analyze the outage performance of the signal-to-noise ratio (SNR)-based selective relaying in a relay network, where the relay terminal may retransmit the received signal or remain silent based on the received SNR of the link from the source to the relay. For the proposed relaying scheme, we derive the exact outage probability.
DCT-Based Subpixel-Accuracy Motion Estimation Utilizing Shifting Matrix
Shin, Jae-Young ; Ryu, Chul ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 372~379
DOI : 10.7840/kics.2015.40.2.372
The latest video compression standard (such as H.264/AVC and HEVC) utilizes quarter-pel accuracy motion estimation in order to retain detailed motion information. Many sub-pixel motion estimation algorithms used in the spatial domain usually encounters increment of computational complexity due to embedded interpolation algorithm. In this paper, an approach to measure sub-pixel accuracy motion estimation in frequency domain using shifting matrix is proposed. Complexity can be reduced utilizing shifting matrix algorithm in frequency domain and simulation results demonstrate not only higher PSNR but lower bit rates than spatial domain algorithms.
Optical Camera Communications: Future Approach of Visible Light Communication
Le, Nam-Tuan ; Nguyen, Trang ; Jang, Yeong Min ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 380~384
DOI : 10.7840/kics.2015.40.2.380
As an extension of Visible Light Communication, Optical Camera Communications (OCC) will be a promising service for smart devices. Especially in line of sight marketing service and indoor localization application, by using camera which exists in smart devices, small amount of data (url link) can be broadcasted or find direction from the illumination system. This paper introduces the operation of wireless communications technology that transmits optical information from optical light source to camera, called Optical Camera Communications.
Noise-Resistant Visible Light Communications Using Subpulse-VPPM
Kim, Jonghun ; Lee, Seungwoo ; Ju, MinChul ; Park, Youngil ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 385~389
DOI : 10.7840/kics.2015.40.2.385
If visible light communication is to be used against large background noise in indoor environment, low frequency noise should be avoided. To maintain the advantages of LED lighting while transmitting signals, LEDs should be dimmable and free from flickering effect. In this paper, the spectrum of transmission signal is shifted toward high frequency for this purpose. Specifically, we propose a subpulse-VPPM scheme, which can be designed using only digital components, and we implement a test-bed for performance measurement.
An LED Positioning Method Using Image Sensor of a Smart Device
Kim, Jae-Hoon ; Kim, Byoung-Sup ; Jeon, Hyun-Min ; Kang, Suk-Yon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 390~396
DOI : 10.7840/kics.2015.40.2.390
The drastic growth of mobile communication and spreading of smart phone make the significant attention on Location Based Service. The one of most important things for vitalizations of LBS is the accurate estimating position for mobile object. Focusing on an image sensor deployed in smart phone, we develop a LED based positioning estimation framework. The developed approaches can strengthen the advantages of independent indoor applicability of LED. The estimation of LED based positioning is effectively applied to any indoor environment. We put a focus especially on the algorithmic framework. of image processing of smart phone. From LED lighting, we can obtain a typical signal image which contains the unique positioning information. Furthermore test-bed based on smart phone platform is practically developed and all data have been harvested from the actual measurement of test indoor area. This can approve the practical usefulness of proposed framework.
Design of a Low Noise 6-Axis Inertial Sensor IC for Mobile Devices
Kim, Chang Hyun ; Chung, Jong-Moon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 397~407
DOI : 10.7840/kics.2015.40.2.397
In this paper, we designed 1 chip IC for 3-axis gyroscope and 3-axis accelerometer used for various IoT/M2M mobile devices such as smartphone, wearable device and etc. We especially focused on analysis of gyroscope noise and proposed new architecture for removing various noise generated by gyroscope MEMS and IC. Gyroscope, accelerometer and geo-magnetic sensors are usually used to detect user motion or to estimate moving distance, direction and relative position. It is very important element to designing a low noise IC because very small amount of noise may be accumulated and affect the estimated position or direction. We made a mathematical model of a gyroscope sensor, analyzed the frequency characteristics of MEMS and circuit, designed a low noise, compact and low power 1 chip 6-axis inertial sensor IC including 3-axis gyroscope and 3-axis accelerometer. As a result, designed IC has 0.01dps/
of gyroscope sensor noise density.
Knowledge Driven Architectural Model to Support Smart Emergency Service in Web of Objects Based Iot Environment
Fattah, Sheik Mohammad Mostakim ; Kibria, Muhammad Golam ; Jeong, Kwanghyeon ; Chong, Ilyoung ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 2, 2015, Pages 408~418
DOI : 10.7840/kics.2015.40.2.408
Virtualizing The Physical Devices And Resources As Well As Conceptual Entities Would Form Vos And Cvos, Which Provides Dynamicity And Intelligence Through Composition And Collaboration For Emergency Services In WoO Based Smart Shopping Mall (WSSM). Semantic Ontology In WoO Platform Supports Dynamic Composition And Collaboration Among Objects, VOs And CVOs To Provide Intelligent Services. This Paper Proposes An Architectural Model Of WoO Platform To Support The Smart Emergency Services In Shopping Mall. A Semantic Ontology Model For Wssm, And Information Reusability And Interoperability Among The Vos And Their Functional Models Have Been Presented.