Hybrid 3D Localization for Visible Light Communication Systems

In this study, we investigate hybrid utilization of angle-of-arrival (AOA) and received signal strength (RSS) information in visible light communication (VLC) systems for 3D localization. We show that AOA-based localization method allows the receiver to locate itself via a least squares estimator by exploiting the directionality of light-emitting diodes (LEDs). We then prove that when the RSS information is taken into account, the positioning accuracy of AOA-based localization can be improved further using a weighted least squares solution. On the other hand, when the radiation patterns of LEDs are explicitly considered in the estimation, RSS-based localization yields highly accurate results. In order to deal with the system of nonlinear equations for RSS-based localization, we develop an analytical learning rule based on the Newton-Raphson method. The non-convex structure is addressed by initializing the learning rule based on 1) location estimates, and 2) a newly developed method, which we refer as random report and cluster algorithm. As a benchmark, we also derive analytical expression of the Cramer-Rao lower bound (CRLB) for RSS-based localization, which captures any deployment scenario positioning in 3D geometry. Finally, we demonstrate the effectiveness of the proposed solutions for a wide range of LED characteristics and orientations through extensive computer simulations.Comment: Submitted to IEEE/OSA Journal of Lightwave Technology (10 pages, 14 figures

A Software-Defined Multi-Element VLC Architecture

In the modern era of radio frequency (RF) spectrum crunch, visible light communication (VLC) is a recent and promising alternative technology that operates at the visible light spectrum. Thanks to its unlicensed and large bandwidth, VLC can deliver high throughput, better energy efficiency, and low cost data communications. In this article, a hybrid RF/VLC architecture is considered that can simultaneously provide light- ing and communication coverage across a room. Considered architecture involves a novel multi-element hemispherical bulb design, which can transmit multiple data streams over light emitting diode (LED) modules. Simulations considering various VLC transmitter configurations and topologies show that good link quality and high spatial reuse can be maintained in typical indoor communication scenarios

A New Formulation For The Fundamental Period Of Reinforced Concrete Planar Shear Walls

The reinforced concrete shear wall system has become a popular structural component for lateral resistance in buildings and base shear of these structures has a vital effect on the earthquake induced lateral forces. The fundamental period of structures is used in most building codes to determine the lateral forces. However, accurate computation of period is not an easy task at the design stage. The main objective of this study is to evaluate the empirical easy-to-use equation for the calculation of fundamental periods of concrete planar shear walls. Genetic programming has been used to generate the proposed formula. Finite element analysis, were carried out for various shear walls having a variety of height and length and the results were used to develop the proposed formula. The outcomes of formula are compared with the results from equations in the seismic codes and finite element analysis. The comparison results indicate good agreement with finite element analysis and show better performance than codes

EVALUATION OF THE CASES WITH TUBOOVARIAN ABSCESSES

Amaç: Kliniğimizde Tuboovarian Abse nedeniyle cerrahi operasyon uygulanan hastalarınretrospektif olarak araştırılarak, klinik ve laboratuar sonuçlarını, uygulanan tedaviyöntemlerini ve gelişen komplikasyonlarını incelemektir.Gereç ve yöntem: Ocak 2003 - Mart 2007 tarihleri arasında tuboovarian abse tanısıile opere edilen 39 hasta retrospektif olarak incelendi. Hastaların klinik ve laboratuarsonuçları, uygulanan operasyon yöntemleri ve gelişen komplikasyonlar kaydedildi.Bulgular: Hastaların %71,7'si multipardı. Hastaların başlıca şikayetleri pelvik ağrı(%92,3) ve ateş (%69,6)'idi. Rahim içi araç kullanımı prevelansı %48,7, son 6 ay içindegeçirilmiş intrauterin veya intraabdominal operasyon prevelansı %33,3 ve pelvikinflamatuar hastalık prevelansı %28,2 olarak saptandı. Klinik bulgu olarak; %69,2 hastada38,3ËšC üzerinde ateş, %64,1 hastada lökositoz, %92,3 hastada yükseksedimentasyon hızı, %89,7 hastada C-reaktif protein yüksekliği tespit edilmiştir. Doğurganlığınıkorumak isteyen hastalara abse drenajı uygulandı. TOA drenajı yapılan hastalarınoranı %71,8 idi. Kullanılan rezektif cerrahi yöntemler arasında; total abdominalhisterektomi oranı (%12,8), unilateral salpingoooferektomi oranı (%10,3), bilateralsalpingoooferektomi oranı (%5,1) saptandı. Hastaların 5'inde (%12,8) intra-operatifkomplikasyon olarak barsak hasarı gelişirken, 4 hastada (%10,3) postoperatif komplikasyonolarak yara yeri enfeksiyonu ve atelektazi gelişti.Sonuç: TOA'yi takip eden yüksek morbidite ve azalmış fertilite oranları nedeniyle erkentanı ve cerrahi müdahale oldukça önemlidir.Objective: The aim of study is retrospective evaluation of the clinical and laboratoryresults, the treatments and complications in patients who were managed for tuboovarianabscess (TOA) clinic in our department.Materials and method: The records of 39 patients who has operated with thediagnosis of tuboovarian abscess between January 2003 and March 2007 were studiedretrospectively. The patients clinical and laboratory results, operational methods appliedand the complications raised were recorded.Results: 71.7% of the patients were multipar. The main complaints of the patientswere pelvic pain (92.3%) and fever (69.6%). Prevelance of intrauterine device (IUD)usage, intrauterin or intraabdominal operations applied in the last 6 months, previouspelvic inflamatuary disease (PID) were as 48.7%, 33.3 %, 28.2%. As clinical andlaboratory signs; in 69.2 % of patients high axillary fever (>38.3ºC), in %64.1 of patientsleukocytosis, in 92.3 % of patients high sedimentation rate and in 89.7 % of patientshigh C-Reactive Protein (CRP) detected. For the patients who would like to preservereproductivity; TOA abscess drainage is applied with a ratio of 71.8%. As resectivesurgery methods that were applied; total abdominal hysterectomy ratio was 12.8 %,unilateral salphingoophorectomy ratio was 10.3 %, bilateral salphingoophorectomy ratiowas 5.1%. Intraoperative complications were observed in 5 (12.8%) patients (bowelinjury) where as postoperative complication were observed in 4 (10.3%) patients(wound enfection and atelectasia).Conclusion: Due to minimizing decreased fertility and high morbidity following TOA; itis important for the women health to apply early diagnosis and early surgery