• Journal of the Korea Society of Computer and Information
• /
• v.12 no.1 s.45
• /
• pp.145-154
• /
• 2007

In this paper, an improved detection method is proposed by supplementing various types of Multi-Path gam for a MMSE Multi-User detecter. This method is proposed to complement the shortcomings of the conventional detection method which is used for multiuser detection in STBC(Space-Time Block Code) CDMA system. We analyzed the improved method in bit error probability viewpoint and compared the result with that of the conventional method. In this result, we showed that the improved method obtains better performance of bit error probability than the conventional method when parameters such as delay, number of user and SNR are changed.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2005.09a
• /
• pp.196-197
• /
• 2005

• Journal of the Korea Society of Computer and Information
• /
• v.9 no.2
• /
• pp.89-96
• /
• 2004

In this paper, an improved method is proposed by supplementing multi-path gain for detection. This method is proposed to complement the shortcomings of the conventional detection method which is used for multiuser detection in STBC(Space-Time Block Code) CDMA system. We analyzed the improved method in bit error probability viewpoint and compared the result with that of the conventional method. From this result, we showed that bit error probability of the improved method is superior to that of the conventional method when the parameters such as delay, number of user and SNR are increased.

• Journal of KIISE:Software and Applications
• /
• v.33 no.4
• /
• pp.402-410
• /
• 2006

This paper presents a method for feature based block motion estimation that uses multi -resolution image sequences to obtain the panoramic images in the continuous ultrasound image sequences. In the conventional block motion estimation method, the centers of motion estimation blocks are set at the predetermined and equally spaced locations. This requires the large blocks to include at least one feature, which inevitably requires long estimation time. In this paper, we propose an adaptive method which locates the center of the motion estimation blocks at the feature points. This make it possible to reduce the block size while keeping the motion estimation accuracy The Harris-Stephen corner detector is used to get the feature points. The comer points tend to group together, which cause the error in the global motion estimation. In order to distribute the feature points as evenly as Possible, the image is firstly divided into regular subregions, and a strongest corner point is selected as a feature in each subregion. The ultrasound Images contain speckle patterns and noise. In order to reduce the noise artifact and reduce the computational time, the proposed method use the multi-resolution image sequences. The first algorithm estimates the motion in the smoothed low resolution image, and the estimated motion is prolongated to the next higher resolution image. By this way the size of search region can be reduced in the higher resolution image. Experiments were performed on three types of ultrasound image sequences. These were shown that the proposed method reduces both the computational time (from 77ms to 44ms) and the displaced frame difference (from 66.02 to 58.08).

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.12 no.3
• /
• pp.125-132
• /
• 2016

The European Telecommunication Standards Institute (ETSI) Technical Committee (TC) Reconfigurable Radio Systems (RRS) is standardizing the multi-mode Mobile Device (MD). The configuration of multi-mode MD is determined by the downloaded mobile communication standard software. In this paper, we introduce the Radio Library concept for multi-mode MD which is one of the key components of RRS standard. This paper also introduces the Standard Functional Block which is a part of Radio Library. A method for selecting efficiency SFBs for multi-mode MD is presented and a Radio Library is generated based on the selected SFBs. This paper also shows sample Standard Functional Block Set which included in Radio Library. In order to verify the compatibility of the generated Radio Library which was made by C language, we implement the LTE Rel-10 and Wi-Fi(802.11b) to show the efficiency of generating a mobile communication standard software based on the Radio Library. Then using the Prograph Visual Programming MartenTM 1.6.4, we compiled our LTE Rel-10 and Wi-Fi(802.11b) source code.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.38 no.4
• /
• pp.335-343
• /
• 2001

The conventional wavelet-based fractal image coding has the disadvantage that the encoding takes a long time, since each range block finds the best domain in the image. In this Paper, we propose wavelet-based fractal image coding using SAS(Self Affine System) method and multi-scale factor. It consists of the range and domain blocks in DWT(discrete wavelet transform) region. Using SAS method, the proposed method is that the searching process of the domain block is not required, and the range block selects the domain which is relatively located the same position in the upper level. The proposed method can perform a fast encoding by reducing the computational complexity in the encoding process. In order to improve the disadvantage of SAS method which is reduced image qualify, the proposed method is improved image qualify using the different scale factors for each level. As a result, there is not influence on an image quality, the proposed method is enhanced the encoding time and compression ratio, and it is able to the progressive transmission.

• Journal of Broadcast Engineering
• /
• v.15 no.2
• /
• pp.232-235
• /
• 2010

This paper proposes an efficient depth-map coding method. The adaptive block-based depth-map coding method decides the number of bit planes to be encoded according to the quantization parameters to obtain the desired bit rates. So, the depth-map coding using the block-based decision of the bit-plane to be encoded proposes to free from the constraint of the quantization parameters. Simulation results show that the proposed method, in comparison with the adaptive block-based depth-map coding method, improves the average BD-rate savings by 3.5% and the average BD-PSNR gains by 0.25dB.

• The Journal of the Korea Contents Association
• /
• v.5 no.1
• /
• pp.201-208
• /
• 2005

Tn this paper, we evaluate the peak-to-average power ratio (PAPR) performance in a space-time block code (STBC) multi-input multi-output orthogonal frequency division multiplexing (MIMO-OFDM) system using selected mapping (SLM) and partial transmit sequences (PTS) approaches. SLM and PTS methods are used to decrease the nonlinear distortion and to improve the power efficiency of the nonlinear high power amplifier(HPA) in the MIMO-OFDM system. In simulation result, when compared with the existing MIMO-OFDM system using QPSK, the PTS method reduces the PAPR about 5dB while the SLM method can reduce about 3.5 dB. Also, we find the BER performance of the MIMO-OFDM system with and without the predistorter in front of the HPA. When the predistorter is used, the input back-off (IBO) of 4 dB is required in the PTS method, and IBO of 6 dB in the SLM method to closely conform to the linear amplifier. If the method of improving the PAPR is not used, the value of IBO of 8 dB is required.

• Journal of Welding and Joining
• /
• v.28 no.1
• /
• pp.54-59
• /
• 2010

Ship Blocks are assembled by welding, and among them, welding between large blocks (Pre-erection stage) is used as feature of butt. In this process, local material has a experience of thermal cycle and become finally shrunk. As for inconsistency of shrunk weldments and adjacent regions, ship structure would be deformed locally and globally. Thermal distortion analyses are done for control of these processes, and methodologies capable of ship block size among them are using 2-D shell element in FEM. A shell element takes charge of plate, so it has its thickness which is important for angular distortion by welding. By the way, a butt-welding consists normally of several passes, and weldment thickness are different at each pass. If a calculated final one-time welding shrinkage is acting on the shell element whose thickness is same as it of plate, then deformation value must be underestimated. This research developed a methodology that total deformation after multi-pass welding can be analyzed by one time at shell element having original thickness of its plate. We use the SDB thermal distortion analysis method and verified by several experiment. The both experimental and analysis results showed good agreements.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2009.01a
• /
• pp.273-277
• /
• 2009

A compressed video stream is very sensitive to transmission errors that may severely degrade the reconstructed image. Therefore, error resilience is an essential problem in video communications. In this paper, we propose novel temporal error concealment techniques for recovering lost or erroneously received macroblock (MB). To reduce the computational complexity, the proposed method adaptively determines the search range for each lost MB to find best matched block in the previous frame. And the original corrupted MB split into for $8{\times}8$ sub-MBs, and estimates motion vector (MV) of each sub-MB using its boundary information. Then the estimated MVs are utilized to reconstruct the damaged MB. In simulation results, the proposed method shows better performance than conventional methods in both aspects of PSNR.