A cell planning and resource allocation scheme called EBRD (Enhanced Bandwidth and Region Division) is presented for improving channel capacity and for maintaining a proper QoS (Quality of Service) over the downlink OFDMA (Orthogonal Frequency Division Multiple Access) system. Through an optimal combination of sectorization and frequency overlay, the EBRD scheme improves both channel capacity and outage probability. In order to analyze the performance of the proposed algorithm, the outage probability is obtained as a closed numerical form. In the simulation, the EBRD scheme outperforms 3-sectorization in terms of throughput and outage probability.

For mobile visual communications, the development of more robust and efficient video traffic control and transmission techniques remains one of the most important issues. Foveated video originates from visual entropy reduction by removing undetectable high visual frequencies that occur at a distance from the fixation point. In this paper, compression gain is defined and measured to quantify the enhanced performance when the visual throughput of the regions of interest (ROI) is increased over a capacity-limited channel.

OFDM-based networks utilizing the frequency reuse factor of 1 may produce the severe ICI (intercell interference) at the cell boundary even though overall cell capacity is increased and network deployment is facilitated. In the forward-link, the ICI may rise above a QoS (quality of service) threshold beyond some distance from BSs (base stations). In this paper, we analyze the forward-link capacity of an MC-CDMA system as a function of the ICI according to the distance from a cell. To achieve this goal, a closed form of the outage probability is derived and utilized to obtain the accommodated number of users and system parameters.

For broadband wireless networks based on OFDM (Orthogonal Frequency Division Multiplexing), an FRF (Frequency Reuse Factor) of 1 has been highly desirable for more improved channel throughput. However, due to the limited power budget of MSs (Mobile Stations) or the increase in ICI (Inter-Cell Interference), a required QoS (Quality of Service) may not be maintained. This paper addresses an optimal LCRTD (Loading Control based on Region-Time Division) over multi-cell environments for an efficient uplink QoS control. In the LCRTD scheme, a cell is divided into several regions by utilizing an optimization approach under QoS constraints, and users in each region are allowed to send their data at the allocated time slots. In the simulation, it is demonstrated that a decrease of 26% in the transmit power can be obtained.

A cell search technique utilizing a known postfix for OFDM (orthogonal frequency division multiplexing) cellular systems is described. The known postfix is generated in the time domain by inserting pilots in the frequency domain and plays the role of the cyclic prefix in general OFDM systems. Since it demonstrates good correlation properties, it can be facilitated to synchronize each symbol with an identified postfix. In this paper, two different known postfixes are allocated to each cell. One is used for cell identification and symbol synchronization, which is designed to be different among neighboring cells. The other is used for frame synchronization and is the same for all cells. In the simulation, the cell search is accomplished with a probability greater than 10-3 at -27 dB in a vehicular channel. Even at -30 dB, the cell search probability is greater than 10-2 in a pedestrian channel as well as 10-3 in the AWGN (additive white gaussian noise) channel.

A radio synchronization technique that dispenses with GPS (Global Positioning System) for OFDM (Orthogonal Frequency Division Multiplexing)-based broadband networks is described. UMTS (Universal Mobile Telecommunications System) employs three main mechanisms, a node, transport channel and radio interface synchronization. The RNC (Radio Network Controller) is used as a key network component for the centralized synchronization mechanism. Here, we explore a more accurate and simpler asynchronous technique for broadband networks from the perspective of a distributed manner, where MSs (Mobile Stations) play an important role in timing adjustment. Propagation delay and the hierarchical synchronization mechanism are taken into account in the mathematical analysis.

An ICI (Inter-Cell Interference) mitigation algorithm for exploiting macroscopic diversity for an up-link OFDMA (Orthogonal Frequency Division Multiple Access) system is proposed. To reduce the influence of carrier collision, the order of resource allocation is coordinated based on the location of each MS (Mobile Station) and the associated carrier group. This consideration significantly reduces ICI and enhances throughput at the boundary region.

Question and Answering (Q&A) sites are recently gaining popularity on the Web. People using such sites are like a community-anyone can ask, anyone can answer, and everyone can share, since all of the questions and answers are public and searchable immediately. This mechanism can reduce the time and effort to find the most relevant answer. Unfortunately, the users suffer from answer quality problem due to several reasons including limited knowledge about the question domain, bad intentions (e.g. spam, making fun of others), limited time to prepare good answers, etc. In order to identify the credible users to help people find relevant answer, in this paper, we propose a ranking algorithm, InfluenceRank, which is basis of analyzing relationship in terms of users' activities and their mutual trusts. Our experimental studies show that the proposed algorithm significantly outperforms the baseline algorithms.

ICI (Inter-Cell Interference) mitigation schemes at the cell border are frequently dealt with as a special issue in 3GPP LTE (Long Term Evolution). However, few papers have analyzed the outage performance for the ICI mitigation schemes. In this paper, we propose a generalized cell planning scheme termed QBPA (Quality of Service based Band Power Allocation). Utilizing the QBPA scheme, we measure how much increase in channel capacity can be obtained through the flexible control of bandwidth and power in multi-cell forward-link environments. In addition, the feasible performance of the conventional schemes can be evaluated as long as those schemes are specific forms of the QBPA.

For the acquisition of visual information, the nonuniform sampling process by photoreceptors on the retina occurs at the earliest stage of visual processing. From objects of interest, the human eye receives high visual resolution through nonuniform distribution of photoreceptors. Therefore, this paper proposes auto exposure and focus algorithms for the real-time video camera system based on the visual characteristic of the human eye. For given moving objects, the visual weight is modeled for quantifying the visual importance and the associated auto exposure and focus parameters are derived by applying the weight to the traditional numerical expression, i.e., the DoM (Difference of Median) and Tenengrad methods for auto focus.

To generate multiple orthogonal carriers in an OFDM (Orthogonal Frequency Division Multiplexing) symbol, an FFT (Fast Fourier Transform) and IFFT (Inverse FFT) pair is utilized at the transmitter and the receiver, respectively. Thus, it may be difficult for an MN (Mobile Node) to reconstruct signals received from several BSs (Base Stations), when single FFT module is used. Moreover, when a GPS (Global Position System) is not supported, ICI (Inter Carrier Interference) may occur over multi-cell environments. This paper introduces a synchronization protocol for OFDM-based asynchronous networks that do not use GPS. The network protocol is designed to perform the plug & access radio configuration for next generation networks.

For point-to-point mobile visual communications, layered video has been utilized to adapt to time-varying channel capacity over noisy environments. From the perspective of the HVS (Human Visual System), it is necessary to minimize the loss of visual quality by specifically maintaining the throughput of visually important regions, objects and so on. Utilizing the prioritized bitstreams generated according to each layer, the throughput can be improved for given channel statistics. In this paper, we define the transmission gain and measure the improved performance when the throughput of ROI (Regions Of Interest) is increased relative to visually unimportant regions over a capacity limited mobile channel.

An FRPA (frequency reuse power allocation) technique by employing the frequency reuse notion as a strategy for overcoming the ICI (intercell interference) and maintaining the QoS (quality of service) at the cell boundary is described for broadband cellular networks. In the scheme, the total bandwidth is divided into sub-bands and two different power levels are then allocated to sub-bands based on the frequency reuse for forward-link cell planning. In order to prove the effectiveness of the proposed algorithm, a Monte Carlo simulation was performed based on the Chernoff upper bound. The simulation shows that this technique can achieve a high channel throughput while maintaining the required QoS at the cell boundary.

This paper presents a coexistence model of IEEE 802.15.4 with IEEE 802.11b interference in fading channels and proposes two adaptive channel allocation schemes. The first avoids the IEEE 802.15.4 interference only and the second avoids both of the IEEE 802.15.4 and IEEE 802.11b interferences. Numerical results show that the proposed algorithms are effective for avoiding interferences and for maximizing network capacity since they select a channel which gives the maximum signal to noise ratio to the system.

We seek a resource allocation algorithm through carrier allocation and modulation mode selection for improving the quality of service (QoS) that can adapt to various screen sizes and dynamic channel variations. In terms of visual quality, the expected visual entropy (EVE) is defined to quantify the visual information of being contained in each layer of the scalable video coding (SVC). Fairness optimization is conducted to maximize the EVE using an objective function for given constraints of radio resources. To conduct the fairness optimization, we propose a novel approximation algorithm for resource allocation for the maximal EVE. Simulations confirm that the QoS in terms of the EVE or peak signal to noise ratio (PSNR) is significantly improved by using the novel algorithm.

This paper presents a numerical analysis of reverse link capacity by obtaining a closed form of ICI (InterCell Interference) over OFDM (Orthogonal Frequency Division Multiplexing)-based broadband wireless networks. In the analysis, shadowing factors are taken into account for determining the home BS (Base Station) of each MS (Mobile Station) over multicell environments. Under the consideration, a more accurate analysis of link capacity can be performed compared to Gilhousen's approximation. In the numerical results, it turns out that the actual interference is lower than Gilhousen's approximation with a decrease of around 20% in the interference.

Due to ease of implementation for various user interactive applications, much research on motion recognition has been completed using Kinect. However, one drawback of Kinect is that the skeletal information obtained is provided under the assumption that the user faces Kinect. Thus, the skeletal information is likely incorrect when the user turns his back to Kinect, which may lead to difficulty in motion recognition from the application. In this paper, we implement a highly accurate human motion capture system by installing six Kinect sensors over 360 degrees. The proposed method enables skeleton to be obtained more accurately by assigning higher weights to skeletons captured by Kinect in which the user faces forward. Toward this goal, the front vector of the user is temporally traced to determine whether the user is facing Kinect. Then, more reliable joint information is utilized to construct a skeletal representation of each user.

The researches on predicting and removing of lithographic hot-spots have been prevalent in recent semiconductor industries, and known to be one of the most difficult challenges to achieve high quality detection coverage. To provide physical design implementation with designer's favors on fixing hot-spots, in this paper, we present a noble and accurate hot-spot detection method, so-called "leveling and scoring" algorithm based on weighted combination of image quality parameters (i.e., normalized image log-slope (NILS), mask error enhancement factor (MEEF), and depth of focus (DOF)) from lithography simulation. In our algorithm, firstly, hot-spot scoring function considering severity level is calibrated with process window qualification, and then least-square regression method is used to calibrate weighting coefficients for each image quality parameter. In this way, after we obtain the scoring function with wafer results, our method can be applied to future designs of using the same process. Using this calibrated scoring function, we can successfully generate fixing guidance and rule to detect hot-spot area by locating edge bias value which leads to a hot-spot-free score level. Finally, we integrate the hot-spot fixing guidance information into layout editor to facilitate the user-favorable design environment. Applying our method to memory devices of 60 nm node and below, we could successfully attain sufficient process window margin to yield high mass production.

The Liquid-crystal display (LCD) overdrive technique has been utilized to reduce motion blur on a display via a reduction in the response time. However, to measure the variation of the pixel amplitudes, it is necessary to store the previous frame using a large frame memory. To downscale the frame memory, block truncation coding (BTC) is commonly employed due to the simplicity of its implementation, even if some visual artifacts may occur for image blocks with high frequency components. In this paper, we present a multimode-multilevel BTC (MBTC) technique that improves performance while maintaining simplicity. To improve the visual quality, we uniquely determine the quantization level and coding mode of each block according to the distribution of the luminance and chrominance amplitudes. For a compression ratio of 6:1, the proposed method demonstrates higher coding efficiency and overdrive performance by up to 3.81 dB in the PSNR compared to other methods.

This paper presents an admission control technique for multi-carrier systems with an FRF(frequency reuse factor) of 1. The FRF of 1 is very attrative for more improved channel throughput but the forward link capacity is rapidly decreased at the cell boundary region due to the increase in the ICI(InterCell Interference). By measuring a region-based channel capacity and deriving a closed form of blocking probability, a QoS(Quality of Service) maintenance technique and mobility model can be acquired. In the simulation, the proposed scheme demonstrates a blocking probability reduction of up to 40% compared to the cell-based link capacity scheme.