Exploiting Trust Degree for Multiple-Antenna User Cooperation

For a user cooperation system with multiple antennas, we consider a trust degree based cooperation techniques to explore the influence of the trustworthiness between users on the communication systems. For the system with two communication pairs, when one communication pair achieves its quality of service (QoS) requirement, they can help the transmission of the other communication pair according to the trust degree, which quantifies the trustworthiness between users in the cooperation. For given trust degree, we investigate the user cooperation strategies, which include the power allocation and precoder design for various antenna configurations. For SISO and MISO cases, we provide the optimal power allocation and beamformer design that maximize the expected achievable rates while guaranteeing the QoS requirement. For a SIMO case, we resort to semidefinite relaxation (SDR) technique and block coordinate update (BCU) method to solve the corresponding problem, and guarantee the rank-one solutions at each step. For a MIMO case, as MIMO is the generalization of MISO and SIMO, the similarities among their problem structures inspire us to combine the methods from MISO and SIMO together to efficiently tackle MIMO case. Simulation results show that the trust degree information has a great effect on the performance of the user cooperation in terms of the expected achievable rate, and the proposed user cooperation strategies achieve high achievable rates for given trust degree.Comment: 15 pages,9 figures, to appear in IEEE Transactions on Wireless communication

Non-Terrestrial Networks for UAVs: Base Station Service Provisioning Schemes with Antenna Tilt

By focusing on unmanned aerial vehicle (UAV) communications in non-terrestrial networks (NTNs), this paper provides a guideline on the appropriate base station (BS) service provisioning scheme with considering the antenna tilt angle of BS. Specifically, two service provisioning schemes are considered including the inclusive-service BS (IS-BS) scheme, which makes BSs serve both ground users (GUs) and aerial users (AUs) (i.e., UAVs) simultaneously, and the exclusive-service BS (ES-BS) scheme, which has BSs for GUs and BSs for AUs. By considering the antenna tilt angle-based channel gain, we derive the network outage probability for both IS-BS and ES-BS schemes, and show the existence of the optimal tilt angle that minimizes the network outage probability after analyzing the conflict impact of the antenna tilt angle. We also analyze the impact of various network parameters, including the ratio of GUs to total users and densities of total and interfering BSs, on the network outage probability. Finally, we analytically and numerically show in which environments each service provisioning scheme can be superior to the other one

Triangular Resection of the Upper Lateral Cartilage for Middle Vault Deviation

Objectives Middle vault deviation has a significant effect on the aesthetic and functional aspects of the nose, and its management continues to be a challenge. Spreader graft and its modification techniques have been focused, but there has been scarce consideration for removing surplus portion and balancing the upper lateral cartilage (ULC). This study aimed to report the newly invented triangular-shaped resection technique (“triangular resection”) of the ULC and to evaluate its efficacy for correcting middle vault deviation. Methods A retrospective study included 17 consecutive patients who presented with middle vault deviation and underwent septorhinoplasty by using triangular resection at a tertiary academic hospital from February 2014 and March 2016. Their outcomes were evaluated pre- and postoperatively including medical photographs, acoustic rhinometry and subjective nasal obstruction using a 7-point Likert scale. Results The immediate outcomes were evaluated around 1 month after surgery, and long-term outcomes were available in 12 patients; the mean follow-up period was 9.1 months. Nasal tip deviation angle was reduced from 5.66º to 2.37º immediately (P<0.001). Middle vault deviation also improved from 169.50º to 177.24º (P<0.001). Long-term results were 2.49º (P=0.015) for nasal tip deviation and 178.68º (P=0.002) for middle vault deviation. The aesthetic outcome involved a complete correction in eight patients (47.1%), a minimally visible deviation in seven patients (41.2%) and a remaining residual deviation in two patients (11.8%). Pre- and postoperative minimal cross-sectional areas (summation of the right and left sides) were 0.86 and 1.07, respectively (P=0.021). Fifteen patients answered about their nasal obstruction symptoms and the median symptom score had alleviated from 6.0 to 3.0 (P=0.004). Conclusion Triangular resection of the ULC is a simple and effective method for correcting middle vault deviation and balancing the ULCs without complications as internal nasal valve narrowing

Psychometric Validation of the Korean Version of Structured Interview for Post-traumatic Stress Disorder (K-SIP)

For diagnosis and management of post-traumatic stress disorder (PTSD), the easily administered assessment tool is essential. Structured Interview for PTSD (SIP) is a validated, 17-item, simple measurement being used widely. We aimed to develop the Korean version of SIP (K-SIP) and investigated its psychometric properties. Ninety-three subjects with PTSD, 73 subjects with mood disorder or anxiety disorder as a psychiatric control group, and 88 subjects as a healthy control group were enrolled in this study. All subjects completed psychometric assessments that included the K-SIP, the Korean versions of the Clinician-Administered PTSD Scale (CAPS) and other assessment tools. The K-SIP presented good internal consistency (Cronbach's α=0.92) and test-retest reliability (r=0.87). K-SIP showed strong correlations with CAPS (r=0.72). Among three groups including PTSD patients, psychiatric controls, and normal controls, there were significant differences in the K-SIP total score. The potential cut-off total score of K-SIP was 20 with highest diagnostic efficiency (91.9%). At this point, the sensitivity and specificity were 95.5% and 88.4%, respectively. Our result showed that K-SIP had good reliability and validity. We expect that K-SIP will be used as a simple but structured instrument for assessment of PTSD

Trust Degree-Based MISO Cooperative Communications with Two Relay Nodes

In this paper, we propose transmission strategies in multiple-input-single-output (MISO) cooperative communications with two relay nodes in cases when the relay nodes have different trust degrees, where the trust degrees represent how much the relay nodes can be trusted for cooperation. For the given trust degrees and channel conditions, we first derive a relay selection strategy that maximizes the expected achievable rate. We then propose a cooperative transmission strategy of relays with an optimal cooperative beamforming vector that maximizes the expected achievable rate, which is a linear combination of weighted channel vectors. Finally, we derive the optimal transmission strategy, which is a mixed strategy between the relay selection and cooperative transmission strategies with respect to the trust degrees. Our analysis and numerical results show that the proposed transmission strategies increase the expected achievable rate by exploiting the trust degrees of the relay nodes, along with the channel conditions

Optic perineuritis simultaneously associated with active pulmonary tuberculosis without intraocular tuberculosis

Letter to the Edito

Acute Angle Closure Glaucoma In A Patient With Miller Fisher Syndrome Without Pupillary Dysfunction

"To report a case of an acute angle closure glaucoma (AACG) in a patient with Miller Fisher syndrome (MFS) without pupillary dysfunction.

Transmission Strategy Against Opportunistic Attack for MISO Secure Channels

For a multiple-input-single-output secure channel, we consider the transmission strategies, including transmission rate and beamformer against opportunistic attack, which eavesdrops or generates jamming signal with certain probabilities. Based on the perfect and partial channel state information of jamming channel, we design the transmission strategies against the jamming, eavesdropping, and both attacks. Then, we provide the optimal transmission strategy in terms of expected secrecy rate for the given attack strategy. © 1997-2012 IEEE.

Risk-Aware Wireless Positioning in Maritime Environment

The evolution of wireless communications systems has promoted various applications that require user positions in various environments including indoor, maritime and aerial environments. This progress has also brought advanced wireless location tracking (i.e., positioning) schemes for many purposes such as military, accident prevention and facility management. In this paper, we propose a risk-aware wireless positioning scheme, where the position information is required for safety. Especially for the maritime environment, we model the risk of the user at each position as a function of location accuracy, geometry, ocean current speed and so forth. Considering the power budget of each user, we optimize the user&#8217;s wireless positioning signal frequency (i.e., the positioning signal broadcasting rate) at each position so that our positioning scheme can minimize the average risk for each user