• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.5
• /
• pp.21-29
• /
• 2008

This paper proposes a carrier frequency of set estimation algorithm for IEEE802.11n system. As IEEE802.11n is a multiple input multiple output(MIMO) system, so there are several combining techniques which are used in multiple receive antenna system. In this paper, we propose hybrid carrier frequency offset estimation algorithms using combining techniques in multiple receive antenna systems, and show that the proposed selection combining carrier frequency offset (CFO) estimation algorithm can estimate carrier frequency offset within 1/10 MSE error at SNR 10 dB in channel B and within 1/2 MSE error at SNR 10 dB in channel D rather than the conventional MIMO CFO one.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.6 no.2
• /
• pp.702-721
• /
• 2012

In the DVB-T2 system with a multiple-input single-output (MISO) transmission mode, Alamouti coded orthogonal frequency division multiplexing (OFDM) signals are transmitted simultaneously from two spatially separated transmitters in a single frequency network (SFN). In such systems, each transmit-receive link may have a distinct carrier frequency offset (CFO) due to the Doppler shift and/or frequency mismatch between the local oscillators. Thus, the received signal experiences dual CFOs. This not only causes dual phase errors in desired data but also introduces inter-carrier interference (ICI), which cannot be removed completely by simply performing a CFO compensation. To overcome this problem, this paper proposes an iterative detection with dual phase errors compensation technique. In addition, we propose a successive-iterative ICI cancellation technique. This technique successively eliminates ICI in the initial iteration by exploiting pre-detected data pairs. Then, in subsequent iterations, it performs a fine interference cancellation using a priori information, iteratively fed back from the channel decoder. In contrast to previous works, the proposed techniques do not require estimates of dual CFOs. Their performances are evaluated via a full DVB-T2 simulator. Simulation results show that the DVB-T2 receiver equipped with the proposed dual phase errors compensation and the successive-iterative ICI cancellation techniques achieves almost the same performance as ideal dual CFOs-free systems, even for large dual CFOs.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.43 no.1 s.343
• /
• pp.49-56
• /
• 2006

This paper describes the design and the verification of IEEE 802.15.4 LR-WPAN 2.4GHz Physical layer for Ubiquitous Sensor Network(USN). We designed the Carrier Frequency Offset(CFO) compensation satisfied the frequency tolerance of IEEE 802.15.4 LR-WPAN and the adaptive matched filter that re-setting of the threshold for the symbol synchronization of the various USN environment. The multiplications is reduced 1/16 by this method each other at i, q phases and has 0.5dB performance improvement in detection probability. Proposed baseband system is designed with verilog HDL and implemented using FPGA prototype board.

• Journal of Broadcast Engineering
• /
• v.17 no.5
• /
• pp.864-875
• /
• 2012

In this paper, we propose a carrier frequency offset estimation method for single-carrier MIMO systems. In the proposed method, phase rotated PN (Pseudo-Noise) sequences are transmitted to prevent a cancelling out of partial PN sequences. After removing a modulation of received PN sequences by multiplying of complex conjugated PN Sequences which are locally generated in receiver, a CFO (Carrier Frequency Offset) is accurately estimated by employing L&R method which is a kind of ML (Maximum Likelihood) estimation algorithm and uses multiple auto-correlatos. In addition, the frequency offset estimation scheme by using channel state information is proposed for accurate CFO estimation in time-varying Rayleigh channel. By performing computer simulations, MSE (Mean Square Error) performance of proposed method is almost same as MSE performance of SISO systems in AWGN channel. Moreover, MSE Performance of proposed method with using channel information is higher than MSE performances of SISO system and conventional method in time-varying Rayleigh channel.

• Korean Journal of Human Ecology
• /
• v.20 no.2
• /
• pp.327-338
• /
• 2011

In order to promote and comprehend marriage immigrants' culture, it is essential to understand the life of their families in their counties. For this study, data by a Philippine CFO(Commission on Filipino Overseas) has been analyzed, and the study researcher has attended an educational program run by the PDOS(Pre-Departure Orientation Seminar). Also, in order to understand the immigrants' families in their country, interviews have been done with some of the CFO employees, people arranged to immigrate to Korea through marriage, and female immigrants who are married. First, Filipino females have a positive attitude toward marriage with a foreign male. Most immigrants are from the rural parts of their country, and their families tend to rely on their daughters more than their sons. Therefore, they decide to marry Korean males and immigrate in order to support their families. However many of them do not have enough information about Korea. Second, Philippine's family system is of bilateral kinship, and traditionally, men and women are treated equally. Therefore, Filipino females tend to be well-educated, outgoing, and vibrant. Thus, they can create an active role in married life for themselves and support their family members. Lastly, based on videos and class materials on the topic of domestic violence that are used in the pre-educational programs for females planning to immigrate to Korea, the content of the program is to be revised.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.48 no.6
• /
• pp.1-5
• /
• 2011

We present the Multi-band orthogonal frequency division multiplexing ultra-wideband (MB-OFDM UWB) technology for increasing the transmission reach of wireless speaker systems. The proposed scheme adopts the Reed-Solomon coding for preventing the random error perfectly and shows the SNR gain in low bit error rate (BER) especially. So, we can increase the maximum reach of MB-OFDM UWB technology since the receiver sensitivity is improved. The simulation environment includes most effects of realistic channel environments such as Additive White Gaussian Noise (AWGN), CM1 channel model, Sampling frequency offset (SFO), Carrier frequency offset (CFO) to improve the simulation accuracy. The simulation results show that the proposed scheme can give a maximum 2 dB SNR gain and increase the transmission reach up to 12.6m.

• Journal of the Society of Naval Architects of Korea
• /
• v.40 no.2
• /
• pp.1-10
• /
• 2003

It is important to understand the flow characteristics such as wave and wake development around a ship for the design of the hull forms with better resistance and propulsive performance. The experimental results explicating the local flow characteristics are also invaluable for validation of the physical and numerical modeling of CFD codes, which are recently gaining acknowledgements as efficient tools for hull form evaluation This paper describes velocity and wave profiles measured in the towing tank for the KRISO 138K LNG Carrier (KLNG) model with propeller and rudder. The results contained in this paper can provide the valuable information on the effect of propeller and rudder on stern flow characteristics of the modern commercial hull form, furthermore, the present experimental data will provide important database for CFO validation.

• KIEE International Transactions on Electrophysics and Applications
• /
• v.3C no.5
• /
• pp.165-170
• /
• 2003

This paper presents development of solid core suspension disc insulators (cap and cap suspension disc insulator) for replacing cap and pin suspension disc insulators in overhead transmission and distribution lines which expose to lightning discharges. By this means the punctured problem caused by steep front surge voltage created by lightning discharge on the lines can be solved. The solid core suspension insulator was designed and constructed based on the dimensions of conventional suspension disc insulators (cap and pin insulators). The insulators are made of alumina porcelain. The electrical and mechanical characteristics of the solid core suspension insulators were carried out. The puncture test was performed in the air by applying steep front impulse voltage with amplitude about 2.5 per unit of 50% flashover (CFO) of the insulator unit at negative standard lightning impulse $1.2/50\;\mu\textrm{s}$ with steepness up to $9200\;kV/\mu\textrm{s}$. The testing results show that solid core suspension disc insulators are not punctured eventhough the steepness of the steep front impulse voltage was increased up to $9200\;kV/\mu\textrm{s}$.

• Journal of Microbiology
• /
• v.43 no.1
• /
• pp.1-10
• /
• 2005

We isolated and cultured bacteria inhabiting solar saltern ponds in Taean-Gun, Chungnam Province, Korea. All of the isolated 64 strains were found to be moderately halophilic bacteria, growing in a salt range of 2-20 %, with an optimal concentration of 5% salt. Bacterial diversity among the isolated halophiles was evaluated via RFLP analyses of PCR-amplified 16S rDNAs, followed by phylogenetic analysis of the partial 16S rDNA sequences. The combination of restriction enzyme digestions with HaeIII, CfoI, MspI and RsaI generated 54 distinct patterns. A neighbor-joining tree of the partial 16S rDNA sequences resulted in the division of the 64 strains into 2 major groups, 45 strains of ${\gamma}-Proteobacteria$ (70.3%) and 19 strains of Firmicutes (29.7%). The ${\alpha}-Proteobacteria$ and Cytophaga-Flavobacterium-Bacterioides groups, which were repeatedly found to exist in thalassohaline environments, were not represented in our isolates. The ${\gamma}-Proteobacteria$ group consisted of several subgroups of the Vibrionaceae (37.5%), Pseudoalteromonadaceae (10.9%), Halomonadaceae (7.8%), Alteromonadaceae (7.8%), and Idiomarinaceae (6.3%). Members of Salinivibrio costicola (29.7%) were the most predominant species among all of the isolates, followed by Halobacillus treperi (12.5%). Additionally, three new species candidates were found, based on similarities of the 16S rDNA sequences to those of previously published species.

• Asian Journal of Business Environment
• /
• v.7 no.2
• /
• pp.5-16
• /
• 2017

Purpose - The purpose of this research study is to make a comparative analysis between corporate governance guidelines 2016 and 2012 and area of further improvement to ensure better governance, accountability and transparency. Research design, data and methodology - This research study is mainly based on the corporate governance guidelines 2016 and 2012 issued by the regulatory authority known as Bangladesh Securities and Exchange Commission (BSEC). Results - This study finds that corporate governance guideline 2012 include some new issues such as criteria and qualification of independent director; some additional statements in the directors' report; mandatory requirement of separation of chairman and CEO; constitution of audit committee; chairman of audit committee; role of audit committee, duties of CEO and CFO on financial statements; and collection of compliance certificate from professional accountant or secretary in compare to corporate governance guidelines 2016. Conclusions - This study suggests that the regulatory authority should include more issues such as tax management and reporting, risk management and reporting; individual and overall performance analysis of the board and independent directors; separate nomination and compensation committee; assessment of true independence of the board and its supporting committees to ensure higher quality of corporate governance and transparency.