Filter and nested-lattice code design for fading MIMO channels with side-information

Linear-assignment Gel'fand-Pinsker coding (LA-GPC) is a coding technique for channels with interference known only at the transmitter, where the known interference is treated as side-information (SI). As a special case of LA-GPC, dirty paper coding has been shown to be able to achieve the optimal interference-free rate for interference channels with perfect channel state information at the transmitter (CSIT). In the cases where only the channel distribution information at the transmitter (CDIT) is available, LA-GPC also has good (sometimes optimal) performance in a variety of fast and slow fading SI channels. In this paper, we design the filters in nested-lattice based coding to make it achieve the same rate performance as LA-GPC in multiple-input multiple-output (MIMO) channels. Compared with the random Gaussian codebooks used in previous works, our resultant coding schemes have an algebraic structure and can be implemented in practical systems. A simulation in a slow-fading channel is also provided, and near interference-free error performance is obtained. The proposed coding schemes can serve as the fundamental building blocks to achieve the promised rate performance of MIMO Gaussian broadcast channels with CDIT or perfect CSITComment: submitted to IEEE Transactions on Communications, Feb, 200

Clean relaying aided cognitive radio under the coexistence constraint

We consider the interference-mitigation based cognitive radio where the primary and secondary users can coexist at the same time and frequency bands, under the constraint that the rate of the primary user (PU) must remain the same with a single-user decoder. To meet such a coexistence constraint, the relaying from the secondary user (SU) can help the PU's transmission under the interference from the SU. However, the relayed signal in the known dirty paper coding (DPC) based scheme is interfered by the SU's signal, and is not "clean". In this paper, under the half-duplex constraints, we propose two new transmission schemes aided by the clean relaying from the SU's transmitter and receiver without interference from the SU. We name them as the clean transmitter relaying (CT) and clean transmitter-receiver relaying (CTR) aided cognitive radio, respectively. The rate and multiplexing gain performances of CT and CTR in fading channels with various availabilities of the channel state information at the transmitters (CSIT) are studied. Our CT generalizes the celebrated DPC based scheme proposed previously. With full CSIT, the multiplexing gain of the CTR is proved to be better (or no less) than that of the previous DPC based schemes. This is because the silent period for decoding the PU's messages for the DPC may not be necessary in the CTR. With only the statistics of CSIT, we further prove that the CTR outperforms the rate performance of the previous scheme in fast Rayleigh fading channels. The numerical examples also show that in a large class of channels, the proposed CT and CTR provide significant rate gains over the previous scheme with small complexity penalties.Comment: 30 page

Modeling Chinese post-90\u272 tourism loyalty to the ex-rival state using the perceived value approach

Purpose – A recent trend in tourism research involves the study of independent Chinese tourists. Yet while post-90s or Generation Z (i.e., born in the 1990s) comprises an important share of nondomestic visitors to Taiwan and other tourist destinations, this segment of the tourist population is currently under-analyzed. As a pioneering piece of research in this area, this survey attempts to understand Chinese tourists of this cohort visiting the long-divided state. Design – This research incorporates the social dimension of perceived value in the ordinarily employed perceived-value model to better understand why Chinese post-90s would like to recommend Taiwan. Methodology – This study samples Chinese students from 12 universities located in the northern, central, southern, and western regions of Taiwan. They were investigated with the selfadministered survey which is composed of five constructs, for a total of 17 questions. Structural equation modeling was employed to analyze the collected data and testify the hypotheses. Findings – The finding provides insights in the specific tourism behaviors of this cohort and how they are found distinct from their predecessors. The emotional dimension of the post-90s’ tourismrelated perceived value is a strong determinant of their loyalty to Taiwan as a tourist destination. The prior-rival situation between both sides of the Taiwan Strait might signify that social dimension significantly predict their loyalty, through the mediator of satisfaction. Originality – This research provides important information for tourism businesses regarding place management and marketing strategies, enabling them to receive this new generation of Chinese customers

Experimental and Numerical Study on the Semi-Closed Loop Control of a Planar Parallel Robot Manipulator

This paper implements the model predictive control to fulfill the position control of a 3-DOF 3-RRR planar parallel manipulator. The research work covers experimental and numerical studies. First, an experimental hardware-in-the-loop system to control the manipulator is constructed. The manipulator is driven by three DC motors, and each motor has an encoder to measure the rotating angles of the motors. The entire system is designed as a semiclosed-loop control system. The controller receives the encoder signals as inputs to produce signals driving the motors. Secondly, the motor parameters are obtained by system identification, and the controllers are designed based on these parameters. Finally, the numerical simulations are performed by incorporating the manipulator kinematics and the motor dynamics; the results are compared with those from the experiments. Both results show that they are in good agreement at steady state. There are two main contributions in this paper. One is the application of the model predictive control to the planar parallel manipulator, and the other one is to overcome the effects of the uncertainties of the DC motors and the performance of the position control due to the dynamic behavior of the manipulator

Reliability of clinical examination methods for postoperative pain after primary root canal treatment

Background/purpose: Clinical test results may have lower reliability due to the varying range of test stimulation or patient subjectiveness. This study aimed to verify a reliable clinical test method by comparing pain intensity levels of a tooth at rest, during function, and after the clinical tests of percussion and chewing.Materials and methods: A total of 36 asymptomatic necrotic teeth that required root canal treatment, one in each patient, were included. All treatment procedures were performed in a single visit by an experienced endodontist. Patients were asked to mark their pain levels on a vertical visual analog scale (VAS) while the relevant tooth was at rest and during function 24 h after the treatment. In addition, patients marked their pain levels after the clinical tests of percussion and chewing. Finally, the pain levels were compared using Pearson's correlation for the reliability of the test methods at a significance level of 95%.Results: The postoperative pain levels measured during the clinical tests and functions were significantly higher than the pain levels at rest (P < 0.05). The pain levels after percussion tests were significantly higher than that during the function and chewing tests (P < 0.05). Pain intensity during the function was simulated with a higher correlation when using the chewing strip method rather than the percussion method.Conclusion: The bite test using the chewing strips as a pain intensity assessment can mimic the actual postoperative pain experience, whereas the percussion test fails to provide the accuracy of this pain experience

Cognitive Radio with Partial Channel State Information at the Transmitter

In this paper, we present the cognitive radio system design with partial channel state information known at the transmitter (CSIT).We replace the dirty paper coding (DPC) used in the cognitive radio with full CSIT by the linear assignment Gel'fand-Pinsker coding (LA-GPC), which can utilize the limited knowledge of the channel more efficiently. Based on the achievable rate derived from the LA-GPC, two optimization problems under the fast and slow fading channels are formulated. We derive semianalytical solutions to find the relaying ratios and precoding coefficients. The critical observation is that the complex rate functions in these problems are closely related to ratios of quadratic form. Simulation results show that the proposed semi-analytical solutions perform close to the optimal solutions found by brute-force search, and outperform the systems based on naive DPC. Asymptotic analysis also shows that these solutions converge to the optimal ones solved with full CSIT when the K-factor of Rician channel approaches infinity. Moreover, a new coding scheme is proposed to implement the LA-GPC in practice. Simulation results show that the proposed practical coding scheme can efficiently reach the theoretical rate performance.Comment: resubmitted to IEEE Transaction on Wireless Communications, May 200

Impacts of Techno-Dependence in The Mobile Instant Messaging Environment

Mobile Instant Messaging (MIM) services such as LINE, WhatsApp, Facebook Messenger and WeChat have already established a mobile communication environment that extends beyond words and sounds. As MIM provides an effective way to communicate, it can improve workplace efficiency, whether within an organization or among offices spread around the world. Nowadays, MIM has been widely accepted as both a social and work tool. The social interaction overload generated by SNSs contributes to emotional exhaustion. Emotional exhaustion, on the other hand, leads to dissatisfaction and discontinuous usage intentions. In the context of MIMs (since they are relative new apps), users whether are likely to experience emotional exhaustion that is generated by social interaction overload, and therefore discontinue their use of MIMs. In contrast to traditional research on IS continued use in the past which defines dependence as a routine and unconscious usage pattern. MIMs offer a communication method that is faster and easier than phone calls or SMS. It is possible that MIMs bring people closer by allowing their users to understand more of the situational matters related to their friends or family, without being limited by distance. Specifically, social-group functions offered by LINE can encourage users to join certain social groups (for instance, family, colleagues, classmates, or friends). Group members can not only discuss common topics, they can also share their “photo albums,” enabling members to enhance their sense of belonging. At the same time, they have the opportunity to feel a sense of being valued, loved, and needed. Although the mobility and accessibility of mobile devices allow users to instantly contact each other on MIMs and on real-time basis, excessive use of MIMs, or MIM techno-dependence, is likely to generate social-related stress among their users. Therefore, this research attempts to explore the possibility that MIM techno-dependency can have non-detrimental effects, and considers the positive and healthy results from MIM techno-dependency due to an increased sense of belonging. The questions explored include: do MIMs users develop a positive techno-dependence? Does this positive emotional reaction encourage MIMs users to continue their use of MIMs? Since LINE is a relative newcomer to MIM, there is still a dearth of research needed to explore issues related to using MIM as a research tool. This study considers how LINE combines a diverse range of communication approaches—such as voice, texts, maps, pictures, photos, locations, video, and audio—with a variety of community groups such as friends chat, group chat, dynamic news, and official accounts. It seems worthwhile to study characteristics of LINE’s users in order to further explore the issues related to MIM. Through the hypotheses development and a survey research on 685 LINE users, this study inferred that users make frequent use of LINE in the long-term mainly because of four kinds of techno-dependence: people, fun, information, and work. Such techno-dependence generates positive and negative consequences concurrently. On the one hand, because the user’s dependence on LINE enhances his or her belongingness through friends, colleagues, and family, this positive social and emotional reaction will make users satisfied with LINE, and thus increase continuous usage intention for LINE. On the other hand, the user’s dependence on LINE means that they experience social interaction overload resulting in emotional exhaustion. Dependence on LINE leads to users experiencing pressure from both social message overload and social demand overload, resulting in social interaction overload. This negative social and emotional reaction will cause a decrease in user satisfaction with LINE, thereby reducing the continuous usage intention of LINE. Based on these findings, we suggest that LINE-related techno-dependence can enable users to increase their sense of positive social belongingness, but can also cause negative social interaction overload. It is concluded that the consequences of techno-dependence are characterized by both positive and negative emotions. Users’ evaluations of LINE are simultaneously affected by positive and negative social and emotional factors

THE NOVEL BIOMECHANICAL MEASUREMENT AND ANALYSIS SYSTEM FOR TUG-OF-WAR

Tug of war (TOW) is a kind of sport that has been accepted as one of the formal items in the Olympic game. Because of having well defined rule, the TOW has high potential to be extended to all over the world in the near future. To increase the possibility of success in the competition, athletes of the TOW should be subjected to a series of training courses. After experiencing certain training course, an athlete of TOW required to carry out pulling force test to evaluate his performance and consequently verify the effectiveness of the training course. In this study, a multi-purposes biomechanical measurement and analysis system is proposed in which various evaluations of the athlete performance. The idea of the proposed system is discussed and the associated theoretical methods are derived