An Analysis Framework for Inter-User Interference in IEEE 802.15.6 Body Sensor Networks: A Stochastic Geometry Approach

Inter-user interference occurs when multiple body sensor networks (BSNs) are transmitting simultaneously in close proximity to each other. Interference analysis in BSNs is challenging due to the hybrid medium access control (MAC) and the specific channel characteristics of BSNs. This paper presents a stochastic geometry analysis framework for inter-user interference in IEEE 802.15.6 BSNs. An extended Matern point process is proposed to model the complex spatial distribution of the interfering BSNs caused by the hybrid MAC defined in IEEE 802.15.6. We employ stochastic geometry approach to evaluate the performance of BSNs, considering the specific channel characteristics of BSNs in the vicinity of human body. Performance metrics are derived in terms of outage probability and spatial throughput in the presence of inter-user interference. We conduct performance evaluation through extensive simulations and show that the simulation results fit well with the analytic results. Insights are provided on the determination of the interference detection range, the BSN density, and the design of MAC for BSNs

Performance Evaluation of Wearable Sensor Systems: A Case Study in Moderate-Scale Deployment in Hospital Environment

A wearable sensor system enables continuous and remote health monitoring and is widely considered as the next generation of healthcare technology. The performance, the packet error rate (PER) in particular, of a wearable sensor system may deteriorate due to a number of factors, particularly the interference from the other wearable sensor systems in the vicinity. We systematically evaluate the performance of the wearable sensor system in terms of PER in the presence of such interference in this paper. The factors that affect the performance of the wearable sensor system, such as density, traffic load, and transmission power in a realistic moderate-scale deployment case in hospital are all considered. Simulation results show that with 20% duty cycle, only 68.5% of data transmission can achieve the targeted reliability requirement (PER is less than 0.05) even in the off-peak period in hospital. We then suggest some interference mitigation schemes based on the performance evaluation results in the case study

Leukemoid reaction associated with transitional cell carcinoma: A case report and literature review

The goal of this article was to investigate the diagnosis, treatment and mechanisms of the leukemoid reaction (LKR) 14 15 associated with transitional cell carcinoma. A 64-year-old male patient presented with anuria. Color ultrasound imaging 15 16 revealed a large bladder tumor. Digital radiography and computerized tomography of the chest, abdomenand pelvis 16 17 revealed only bilateral hydronephrosis, but did not reveal any metastasis. The pre-operative white blood cell count in 17 18 the peripheral blood consistently increased to 58,400/mm3 while neutrophil granulocyte count was 54,900/mm3, without 18 19 fever. Radical  cystectomy and construction of bilateral cutaneous ureterostomy was performed. The histological diagnosis 19 20 was transitional cell carcinoma, Grade 3. Granulocyte colony-stimulating factor (G-CSF) staining was positive in tumor 20 21 cells. Results: After surgery, the leukocyte value became nearly normal. At 3 months later, patient was admitted to our 21 22 hospital with the complaints of the left leg edema, diagnosed as pelviclymph node metestasis. Patient died of systemic 22 23 metastasis within 6 months after the cystectomy. Bladder cancer associated with LKR, though rare, is considered highly 23 24 malignant, difficult to diagnose and as having poor progKey words: Bladder cancer, immunohistochemistry, leukemoid reaction, lymphatic metastasi

Spin relaxation in submonolayer and monolayer InAs structures grown in a GaAs matrix

Electron-spin dynamics in InAs/GaAs heterostructures consisting of a single layer of InAs (1/3-1 monolayer) embedded in (001) and (311)A GaAs matrix was studied by means of time-resolved Kerr rotation spectroscopy. The spin-relaxation time of the submonolayer InAs samples is significantly enhanced, compared with that of the monolayer InAs sample. The electron-spin-relaxation time and the effective g factor in submonolayer samples were found to be strongly dependent on the photogenerated carrier density. The contribution from both the D'yakonov-Perel' mechanism and Bir-Aronov-Pikus mechanism are discussed to interpret the temperature dependence of spin decoherence at various carrier densities. © 2009 The American Physical Society.published_or_final_versio

Weight analysis of influencing factors of dam break risk consequences

There are numerous influencing factors of the risk consequences of dam break. The scientific and reasonable index system and its weight distribution are some of the key elements for comprehensive evaluation of the dam break risk. Taking into consideration 20 factors, including hazards, exposure and vulnerability, the evaluation index system of the consequences of dam break risk is constructed. Using the Statistical Cloud Model (SCM) to improve the entropy method, we establish the weight calculation model of the influencing factors of dam break risk consequences. The results shows that the top five factors with the highest weight are risk population, flood intensity, alert time, risk understanding and distance from the dam. Compared to traditional algebraic weight calculation methods, the result is basically consistent with the algebraic weight distribution, and increases the range by 2.03 times, supporting a more scientific basis for recognizing and evaluating dam break risk consequences.</p