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Stereo matching has a critical disadvantage in that 3D data acquired with this method is not accurate because only intensity data from the image can be utilized. Optimization processes such as belief propagation and graph cuts increase the robustness and accuracy of the 3D data, but these require significant computational power. We propose a novel method of stereo matching that utilizes surface normal data derived from the photometric stereo technique. We obtain an improved depth map without requiring additional optimization.

In this study, a series of 1-g shaking-table tests was performed for a single pile in soft clay deposit with various conditions. Based on the test results, the dynamic p–y curve was determined by c...

In this paper, we investigate the outage probability of a multiuser multiple-input multiple-output (MU-MIMO) system in the heterogeneous network (HetNet) in the presence of unpredictable interference (UI) from coexisting ad hoc systems. In order to achieve multiuser diversity gain, the MU-MIMO system requires feedback carrying the signal-to-interference-plus-noise ratio (SINR) from all active users to the base station. However, the coexisting ad hoc systems in HetNet can unpredictably initiate their data transmission during the SINR feedback duration. This unpredictable behavior by the coexisting ad hoc systems causes a mismatch between the measured SINR and the instantaneous SINR. In order to investigate the performance of the MU-MIMO system in HetNets, we first categorize the interferences into predictable interference and UI. Based on this categorization, we analyze the outage probability of an MU-MIMO system using a max-SINR scheduler. The theoretical analyses show that the MU-MIMO system cannot achieve the maximum diversity gain, since the UI from the coexisting systems causes beam selection mismatch. Additionally, we show that reducing the interval between the measurement and data transmission prevents performance degradation by reducing the effect of the unpredictable behavior of the coexisting ad hoc systems.

This letter proposes a new mode selection scheme to improve the overall packet rates for device-to-device (D2D) communications systems in the bursty traffic model. We consider three types of D2D modes, i.e., dedicated mode, cellular mode, and reuse mode. In the full-buffer traffic model, if all the uplink (UL) channels are occupied by cellular users, the dedicated and cellular modes are not available for D2D user equipments (DUEs) to choose. However, in bursty traffic model, the traffic load is time-varying and DUEs have the option to select the dedicated or cellular modes. To determine the best mode for a DUE in the bursty traffic, we propose a mode selection scheme, which considers the traffic load for the bursty traffic model. Numerical results show that the proposed scheme achieves a remarkable enhancement in average end-to-end delay, dropping probability, and packet rate.

Load and resistance factor design (LRFD) is a limit state design method that has been applied worldwide. Because the data for determining LRFD factors in Korea has been insufficient, the resistance factors suggested by American Association of State Highway and Transportation Officials (AASHTO) in the US have been used for design in Korea, however, these resistance factors were defined based on the characteristics of the predominant bedrock types in the U.S. As such, it remains necessary to determine resistance factors that reflect the bedrock conditions in Korea. Accordingly, in this study, LRFD resistance factors were determined using 13 sets of drilled shaft load test data. To obtain accurate resistance factors, calibration of the elastic modulus of the drilled shaft and the equivalent load&ndash, displacement curve considering the axial load and elastic settlement was conducted. After determining accurate resistance values, a reliability analysis was performed. The resistance factors were determined to be within 0.13&ndash, 0.32 of the AASHTO factors for the shaft resistance, 0.19&ndash, 0.29 for the base resistance, and 0.28&ndash, 0.42 for the total resistance. This is equivalent to being 30&ndash, 60% of the AASHTO-recommended values for the shaft resistance and 40&ndash, 60% of the AASHTO-recommended values for the base resistance. These differences in resistance factors were entirely the result of discrepancies in the conditions of the rock in the US and Korea in which the shafts were founded.

Licensed band communication systems have recently begun trying to utilize unlicensed bands. Due to lack of coordination, however, this spectrum utilization results in strong interference to other unlicensed band equipment (UBE). This problem highlights the need for coexistence scenario that will prevent UBE performance degradation. In this paper, we propose a new access control mechanism for downlink cellular networks using the unlicensed band. First, we analyze the impact of the cellular networks on the UBE outage performance. Based on the analysis, we then obtain a decision threshold for the unlicensed band access control. In the proposed control mechanism, the decision threshold is adaptively controlled by considering the density of the UBE. The numerical results demonstrate that the proposed access control mechanism guarantees the UBE's target performance under various network circumstances.

In this paper, we investigate the impact of outdated channel state information (CSI) on the channel capacity of an opportunistic relaying system in conjunction with adaptive transmission techniques. We derive the closed-form expressions of the channel capacity and its associated outage probability for four adaptive transmission techniques: (1) optimal rate adaptation with constant transmit power, (2) optimal transmit power and rate adaptation, (3) channel inversion with fixed rate, and (4) truncated channel inversion with fixed rate. Analytical and numerical results show the effects of outdated CSI on the capacity of the optimal power and rate adaptation and the sub-optimal channel inversion techniques. In addition, we compare the channel capacity among various adaptive transmission techniques in the presence of outdated CSI, thereby illustrating the intuitive tradeoff between the achievable capacity and implementation complexity.

This chapter aims to provide a comprehensive study of the interference generated by enabling device-to-device (D2D) communication in cellular networks. We first categorize the D2D interference according to its causative factor, and investigate the characteristics and effects. Based on these results, we discuss the necessity of the interference management strategy. We then explore the features, strengths, and weaknesses of existing interference management strategies in the D2D communication. Based on the comparison from among the existing approaches, we highlight the design insights or useful intuition to an efficient interference management strategy. Finally, we provide an open issue relevant to the interference problem regarding the coexistence of the D2D pair and small-cell network, which may be an important subject for further research in D2D communication.

We propose a new robust timing recovery algorithm with small symbol timing jitter for orthogonal frequency-division multiplexing (OFDM) systems. The concept of coarse FFT window selection and adaptive reference pilot generation are employed in this paper. This proposed scheme avoids inter-symbol interference (ISI) as well as delayed locked loop (DLL) tracking failure over frequency selective time-varying channels. In addition, the proposed algorithm has much smaller and smoother steady state DLL tracking error than the conventional algorithm.