Applied Mechanics and Materials Vol. 577

Abstract: This paper offers a DMO (direct mode operation) design applied to TD-LTE. It can support point to point full-duplex communication in the no signal covered area and user switching according to their priority at the same time. The design divides channel into access channel and communication channel to improve the spectrum efficiency. When the SNR is higher than 16dB, the DMO design using QPSK modulation has a BER (bit error rate) reaching 10^-4 under ITU-R M1225 channel B. Although at the same BER value, the SNR requirements of IFDMA has a 0.5dB lower than LFDMA, given that TD-LTE uses LFDMA and LFDMA has a good resistance to frequency offset and is much easier to realize, we adopt LFDMA as subcarrier mapping method in the DMO design. Besides, at the same BER value, the required SNR of MMSE (minimum mean square error) equalization is 1.0~1.5dB lower than the required SNR of the ZF (zero-forcing) equalization. Therefore DMO should use MMSE equalization in the low SNR environment and ZF equalization in the high SNR environment.

Abstract: Time and frequency recursive least squares algorithm (TF-RLS) is proposed to cancel the interference due to the frequency offset (FO) in uplink Orthogonal Frequency Division Multiple Access (OFDMA) system. TF-RLS algorithm is composed of two stages, which is TD-RLS scheme and FD-RLS scheme. In the first stage, TD-RLS scheme is selected to pre-cancel the frequency offset in the time domain, and then the interference induced by residual frequency offset has been eliminated by the FD-RLS scheme in the frequency domain. The result of bit error rate (BER) shows that its performance is robust for cancellation as comparison criteria, even though the frequency offset is 0.45. The 16QAM constellation figures are also simulated to observe the improvements from the proposed suppression schemes.

Abstract: Three-dimensional video technology is becoming more and more popular, because it can provide a better natural depth perception. In this paper, a stereoscopic video player for a time-division display is designed and implemented, and people can use 3D Shutter Glasses to watch stereoscopic video by the player. It mainly focuses on the process of designing a Direct3D application, and the special handling of NVIDIA 3D Vision system for stereoscopic video. Upon examination, the stereoscopic video player can provide stereoscopic perception and good immersive experience.

Abstract: Peterson mutual exclusion algorithm is a concurrent programming algorithm for mutual exclusion that allows two processes to share a single-use resource without conflict, using only shared memory for communication. DiVinE is a LTL model checker, and DVE is the specification language. In this paper, we implement the DVE model of Peterson mutual exclusion algorithm, and verify LTL properties of Peterson mutual exclusion algorithms using DiVinE model checker. The experimental results show that the LTL formula structure is relevant to the costs of LTL verification.

Abstract: In the paper, the resource scheduling algorithm in the downlink of LTE-Advanced (LTE-A) assuming equal power allocation among subcarriers which adopted the technology of carrier aggregation (CA) is investigated. When the independent scheduling (INS) scheme is applied, the LTE users will acquire few resources because they cannot support CA technology. And the fairness of the system is disappointing. Focusing on the problem, a novel proportional fair (PF) scheduling algorithm based on INS is proposed. In the proposed method, the system fairness is well improved without bringing high complexity to the system. And also, we design a weigh factor which is related to the number of the carriers and the percentage of LTE users in the method. The simulation results show that the proposed algorithm can effectively increase the throughput of LTE users and improve the system fairness.

Abstract: Path-based fault-localization technique is proved to be more effective than coverage-based fault localization because of analyzing the semantics of a program. Most previous work focused on investigating coverage-based test-suite reduction approach for fault localization. But it is not suitable for path-based fault localization, because it only analyzes coverage information, and does not take the execution path information of test cases into account. In this paper, we propose a test-suite reduction approach for path-based fault localization. This approach analyzes the concrete execution path of test cases. The experimental results show that the proposed method works well in improving the effectiveness of path-based fault localization.

Abstract: A metadata management mechanism on the basis of HDFS was proposed in this paper, which is applied for cloud storage. The basic unit of consistent hashing is DHU in the scheme. Metadata is distributed in multiple servers in this solution, and the position of metadata is recorded in a mapping table. In addition, prefetching strategy and local cache technology are used to improve the performance of the system. Operation logs and Multi-Paxos algorithm are being used to ensure system’s reliability and consistency. Improved system with a lower latency in reading and writing than the original system was seen in the experiments. Good performance for cloud storage system can be shown by this system.

Abstract: HEVC video coding standard is the next generation of H.264 coding standard, which is able to achieve twice coding efficiency compared with H.264/AVC High Profile. This paper analyzes the key features of HEVC standard based on HEVC reference software HM12.0. Experiments cover different resolutions ranging from 240p to 1600p. The most complex parts of HEVC decoder are intra prediction, loop filter and inverse transform when video sequences are coded with all-intra configuration. When video sequences are coded in random-access configuration, HEVC decoding process is occupied by motion compensation, which takes nearly half of the decoding time. Experiment results indicate that HEVC standard can achieve 50% average bit-rate saving compared with H.264.

Abstract: Aimed at the defects and deficiencies of traditional automotive ECU (Electronic Control Unit) development methods, AUTOSAR as a new standard for automotive software development makes the software development process simplified greatly. The existing AUTOSAR development tools are studied and compared in this article to analyze of their respective characteristics, and an ECU software design scheme of the system is summarized according to the methodology. The research results prove that AUTOSAR can raise the development efficiency and software portability.

Abstract: Shading can smooth the appearance of polygons by reducing the effects of sharp edges, which makes drawn graphics more realistic. Consider factors related to the object surface brightness, analyze and compare several shading algorithms, focus on presenting spherical linear interpolation of the Phong shading, and use OpenGL to realize the procedures and effect diagrams of Flat shading and Gouraud shading in VC + + environment.