Humor Hwang

New Techniques to Reduce Sidelobes in OFDM System

In this paper, we consider out-of-band radiations caused by high sidelobes in orthogonal frequency division multiplexing (OFDM) system. Suppression of sidelobes in OFDM system allows higher spectral efficiency and less interference with existing legacy systems in OFDM based overlay system. We combine different sidelobe suppression techniques to suppress the sidelobes in OFDM system. The multiple-choice sequence (MCS) is combined with cancellation carriers (CCs) and also MCS is combined with subcarrier weighting (SW) technique. MCS is applied prior to CCs or SW techniques. Simulation results show that combining MCS with CCs and MCS with SW techniques the sidelobes in OFDM system can be significantly reduced, which allow a successful co-existance between OFDM overlay system and an existing legacy system.

Interpretation Works and Online Terminology Information System for the Standardization of Smart Grid Terminologies

Power system technologies in the area of smart grid are being converged with communication system technologies or information technologies(IT). This interdisciplinary action affects on two parts vigorously so that IT has become a essential part of power industry. But terminologies of two parts are confused and it is necessary that these are standardized to develop the industry. The interpretation works with scientific and technological standard of the smart grid terminologies which are IEC TC 57 glossary and non-glossary terminologies are introduced. Based on the interpretation works of the smart grid terminologies, an online terminology information system for the standardization of smart grid terminologies is proposed. The system provides the capability of collection and delivery of academic society opinions for the selected and interpreted terminologies.

Standardization of IEC Terminologies Based on a Matrix Classification System

Abstract - Through the correspondence works with IEC in the smart grid fields and power IT fields, we set up the interpretation work procedure and defined the work rule for correspondence by analyzing the work results. In addition, we suggest cases for discussion of terms and definitions in the IEC and analyze them and then propose a matrix classification system for standardization to solve the cases for discussion. The matrix classification system with 3-axes of classification has been applied to newly emerging terminologies followed by smart gird. We drew the usefulness in search of terms in application fields and showed the cases of applying the matrix classification. The IEC Electropedia classification standard is unclear and the classification is mixed with principle, application and product areas. We proposed a new working group in IEC TC1 for research on the matrix classification system and then TC 1 decided to organize a new WG titled in the “IEV structure and supporting tools”.Key Words : Standardization, IEC Terminologies, Matrix classification system, IEC Electropedia, IEC TC1†Corresponding Author : Dept. of Information and Communicatio nEngineering, Myongji University, koreaE-mail: hmhwang@mju.ac.kr* School of Electrical Engineering, Hongik University, Korea.**Dept. of Computer Science, Sookmyung Women’s University, korea.Received : December 31, 2014; Accepted : February 26, 2015

Writing System of the Open Korean Knowledge Dictionary for Standardization of Smart grid Terminologies

Power system technologies in the area of smart grid are being converged with communication system technologies or information technologies(IT). This interdisciplinary action affects on two parts vigorously so that IT has become a essential part of power industry. But terminologies of two parts are confused and it is necessary that these are standardized to develop the industry. The writing system of the Open Korean Knowledge Dictionary for standardization of smart grid terminologies which are IEC TC 57 glossary and non-glossary is proposed. The writing system includes the process of collection, writing guideline and standardization of terminologies. Writing results of 90,000 terminologies for electricity, communication and computer fields including smart grid terminologies, which are registered in the Open Korean Knowledge Dictionary, are shown. The system provides the capability of collection and delivery of academic society opinions for the selected and interpreted terminologies through the internet for standardization and industry propagation of smart grid terminologies.

A Globally Converging Blind Carrier Phase Offset Recovery Scheme for 8-VSB Signals

This paper presents a decision directed blind adaptive algorithm for carrier phase offset recovery of 8-VSB. The algorithm achieves phase recovery by minimizing the quadrature leakage into the in-phase component and removes undesirable local minima, which occur in most blind algorithms, by configuring the reliable leakage estimation region.

An Observation Method for Estimating Carrier Frequency Offset in OFDM Systems

Orthogonal Frequency Division Multiplexing (OFDM) is widely considered as an effective approach for current and future high-speed wireless communication. However, one of the main drawbacks of the OFDM is that it is sensitive to carrier frequency offset (CFO). The CFO causes interference among the multiplicity of carriers in the OFDM signal. Thus, the CFO must be estimated and compensated for in OFDM communication systems to minimize adverse effects of inter-carrier interference on the signal and maintain orthogonality. We propose a method based on observation training symbols for estimating CFO by employing block-by-block estimation. An analytical expression for the mean squared error of the frequency synchronization scheme is given and the results show that the proposed method has a superior performance compared to the conventional methods.

A New Terminology Classification System for the Open Korean Knowledge Dictionary and Reclassification

A new classification system with 9 main categories and 56 subcategories for the Open Korean Knowledge Dictionary is proposed. The classification system setup is to prepare for the standard classification system to be used to manage effectively vast of terminologies which were published in the Open Korean Knowledge Dictionary and is meant to enhance the fifteen-year old classification system for the standard korean great dictionary to match up to the trend of the modern terminology. The new terminology classification system covering all the academic areas such as humanity, sociology, politics, science, medicine, agriculture, engineering, etc, is designed and proposed after investigating several classification systems. The classification system setup procedures follow as ◦ The classification system is designed and planed by both the classification system and the academic expert. ◦ Classification system design covers all the academic areas following National Science and Technology standard classification system after investigating several classification systems such as the National Research Foundation, National Science and Technology Standard Act, Ministry of Knowledge Economy. ◦ Poll and survey is made to collect comments from total 93 members of several academic areas. ◦ The poll result is reviewed among working group members and utilized to update the new terminology classification system. Reclassifications are made for the around 200,000 terms in electricity, computer, medicine, pharmacy, biology, and economics according to the new terminology classification system.

Frequency Offset Estimation Technique for MB-OFDM Based UWB Systems

We propose a new frequency offset estimation technique for multiband orthogonal frequency modulation (MB-OFDM) based ultra wideband (UWB) systems. The proposed frequency offset estimation technique is related to the scheme of Schmidl for channel model 1 (4-1Om NLOS, rms. delay =14.3㎱.) using more than two symbols and with alternate symbols. Variance of frequency offset estimate obtained from the proposed frequency offset estimation technique approaches very nearing to Cramer Rao Lower Bound (CRLB) in an AWGN channel. BER performance of the proposed technique is also presented.

Erratum to "A fine carrier recovery algorithm robust to doppler shift for OFDM systems" [Aug 10 1218-1222]

In this paper, a fine carrier recovery algorithm is proposed to maintain a good performance even with Doppler shifts for OFDM systems. It estimates the frequency offset by utilizing two correlation values for intentionally added positive and negative frequency offsets. Its performance is compared with conventional algorithms such as Beek and Moose algorithms.

RFID Connectivity with STB for Viewer Identification in IPTV

This paper presents the application of RFID (radio frequency identification) to identify the viewer in IPTV (Internet protocol television). RFID reader developed connects serially with IPTV STB (set-top box) for authentication of viewer and service verification by identifying viewer tag wirelessly.