Using a data mining approach for the prediction of user movements in mobile environments

Cataloged from PDF version of article.Mobility prediction is one of the most essential issues that need to be explored for mobility management in mobile computing systems. In this thesis, we propose a new algorithm for predicting the next inter-cell movement of a mobile user in a Personal Communication Systems network. In the first phase of our three-phase algorithm, user mobility patterns are mined from the history of mobile user trajectories. In the second phase, mobility rules are extracted from these patterns, and in the last phase, mobility predictions are accomplished by using these rules. The performance of the proposed algorithm is evaluated through simulation as compared to two other prediction methods. The performance results obtained in terms of Precision and Recall indicate that our method can make more accurate predictions than the other methods.Yavaş, GökhanM.S

Fabrication and characterization of MgB2 powders and Cu-Clad MgB2 wires

Thesis (Master)--Izmir Institute of Technology, Physics, Izmir, 2005Includes bibliographical references (leaves: 56-61)Text in English; Abstract: Turkish and Englishxi, 61 leavesIn 2001, a new superconducting material, MgB2 (39K), which raised new hopes for electrical power applications due to its superior superconducting properties was discovered.In the first part of this study, elementary B is obtained by reacting B2O3, and Mg in Argon atmosphere at 800°C. EDX results revealed that the powder obtained was Boron in 93% purity with Mg as a major impurity. MgB2 is produced from acquired B and Mg in Ar atmosphere at 900°C by a conventional solid-state reaction. MgB2 powders were pressed to a pellet at 500°C at 1 GPa. Microstructural properties of MgB2 were determined by XRD, EDX, and SEM techniques. Electrical properties of fabricated MgB2 were analyzed by resistivity measurements with closed-cycle cryopump system between 20 and 300K. It is found that the Tc onset value of the pellet is around 32K. In the second part, different weight ratios of C is added to commercial MgB2 and pressed at 500°C at 1 GPa. R-T measurements revealed that transition temperature increases with an increase in the C addition concentration. In the third part, MgB2/Mg composite wires were prepared by packing blend of MgB2 and Mg powders inside Cu tubes using PIT method. The microstructure studies MgB2 and Mg powders inside Cu tubes using PIT method. The microstructure studies using XRD, EDX and SEM techniques showed that MgCu2 layer forms at the interface between Cu sheath and core because of Mg diffusion from superconducting core, and excess Mg prevents further reaction of Cu with MgB2. R-T measurements were performed to investigate the influence of excess Mg on Tc. The effect of annealing showed that excess Mg gives better results at annealing temperature of 400°C for 2 hours

The determination of drought resistance characters in Aegean region's wheat cultivars

Ege bölgesi koşullarında özellikle tane dolumu döneminde meydana gelen kuraklıklar verimde büyük ölçüde düşüşlere neden olmaktadır. Bu amaçla, Golia 99, Basribey 95, Cumhuriyet 75, Sagittario, Pamukova 97 ve Negev ekmeklik buğday çeşitlerinin kuraklığa toleransları değerlendirilmiştir. Çalışma, 2007-2008 ve 2008-2009 yıllarında sulu ve susuz koşullarda tarla denemeleri, saksı denemeleri ve çimlenme gözlemleri olmak üzere 3 aşamada yürütülmüştür. Tarla çalışmalarının ilk yılında, bitki boyu, metrekarede başak sayısı, başakta başakçık sayısı, yaprak kuruma oranı, başakta tane sayısı, tane verimi ve hasat indeksi yönünden; ikinci yılda ise; metrekarede başak sayısı, başaklanma gün süresi, başakta başakçık sayısı, tane dolum süresi, başakta tane sayısı, bin tane ağırlığı ve hasat indeksi yönünden uygulamalar x çeşit interaksiyonunun önemli olduğu saptanmıştır. İncelenen özellikler birlikte değerlendirildiğinde, susuz koşullara dayanıklılık yönünden tarla çalışmalarında bitki boyu, metrekarede başak sayısı, yaprakkuruma oranı ve bitki örtüsü sıcaklık değişiminin; saksı çalışmalarında PEG uygulamasında bayrak yaprağı duruş açısı, kardeşlenme öncesi NVDİ değeri ve sapa kalkma döneminde kök uzunluğunun; çimlenme çalışmalarında ise PEG uygulamasında koleoptil uzunluğunun dikkate alınması gerektiği sonucuna varılmıştır. Çeşitler karşılaştırıldığında ise Cumhuriyet 75, Negev ve Sagittario çeşitlerinin susuz koşullarda daha verimli olabileceği ve bu çeşitlerin kuraklığa dayanıklılığı amaçlayan ıslah çalışmalarında başarıyla kullanılabileceği söylenebilir.The drought which was occurred during especially grain filling in Aegean Region leads to significantly declined yield. For this purpose, bread wheat varieties which were Golia 99, Basribey 95, Cumhuriyet 75, Sagittario, Pamukova 97 and Negev were evaluated for drought tolerance. The study was conducted irrigated and rainfed conditions as field trials, pot trials and germination observations in three phases in 2007-2008 and 2008-2009. The applications x variety interactions were determined as important for the properties except for the flag leaf area, heading date, grain filling duration and thousand seed weight in the first year of field study and the except for all examined characteristics by plant height and flag leaf area in the second year. The examined characters were evaluated, in terms of resistance to non-irrigated conditions the plant height, spike number per square meter, the rate of dry leaves and normalized difference vegetation index in field, flag leaf stance, the value of NDVI at tillering and root length at jointing in pots with PEG application, and coleoptile length in germination studies with PEG was concluded to be taken into consideration. When the varieties were compared Cumhuriyet 75, Negev and Sagittario may be more efficient in drought years and these varieties can be said to use succesfully the drought resistance breeding studies

Effect of pulsed electromagnetic field on pain, functionality and quality of life in the treatment of chronic non-specific low back pain: a randomized controlled trial

Background: Pulsed electromagnetic field therapy is a new device and its efficiency on pain treatment needs to be clarified. Our aim is to investigate the effects of PEMF therapy in combination with conventional physical therapy modalities in patients with chronic non-specific low back pain. Methods: Prospective, randomized, patient-blinded, controlled trial with twenty-nine subjects having chronic nonspecific LBP were randomized into experimental and control groups. The experimental group received PEMF in addition to conventional physical therapy, whereas the control group received a sham electromagnetic field with conventional physical therapy for ten sessions over a four-week period. Pain intensity, functional disability and lumbar range of motion measures were collected. Results: Twenty-seven participants with chronic non-specific LBP completed the study (Experimental group N=13, control group N=14). There were significant within-subject effects and treatment*time effects for pain intensity, ODI, and lumbar ROM results. The change in pain intensity (p=0.004), ODI (p=0.012) and lumbar ROM (p<0.001) were significantly higher in the PEMF group compared to the control group. Conclusions: Compared to conventional physical therapy, combining PEMF therapy with conventional physical therapy provides greater clinical improvement in terms of pain intensity, functional disability and lumbar ROM in subjects with non-specific LBP.

Cryopreservation of Nile Tilapia (Oreochromis niloticus) Sperm

The main aim of this study is to determine the effect of the straw volume (0.25 vs. 0.5 mL) on Nile tilapia sperm quality after cryopreservation. Sperm was frozen according to conventional slow freezing procedure and diluted at ratio of 1:3 with ionic extender containing 350 mM glucose and 30 mM Tris containing 10% dimethylacetamide. Diluted semen was equilibrated at 4°C for 10 min and drawn into 0.25-mL or 0.5-mL plastic straws and sealed with polyvinyl alcohol. Samples were frozen 3 cm above of the liquid nitrogen surface and exposed to the liquid nitrogen vapor (≈−140°C) for 10 min. After this, frozen sperm cells were kept into the liquid nitrogen container (−196°C). The frozen sperm in different volume of straws were thawed in a water bath at 30°C for 20 s (0.25-mL straws) or at 30°C for 30 s (0.5-mL straws), respectively. Fertilization was conducted using 1 ×105 spermatozoa/egg ratio with each straw type. The findings of the present study indicated that cryopreservation of sperm in glucose-Tris–based extender using 0.5-mL straws improved post-thaw progressive motility, duration of progressive motility, and fertilization results (P0.01). In conclusion, our results suggest that Nile tilapia sperm can be successfully cryopreserved in Tris-based extenders supplemented with glucose containing 10% dimethylacetamide in 0.5-mL straws

The effects of native and light induced defects in the optical and electronic properties of hydrogenated amorphous silicon germanium (a-SiGe:H) alloy thin films

Thesis (Master)--Izmir Institute of Technology, Physics, Izmir, 2005Includes bibliographical references (leaves: 100-104)Text in English; Abstract: Turkish and Englishxiv, 117 leavesHydrogenated amorphous silicon-germanium alloy thin films (a-SiGe:H) of various germanium concentrations, are potential candidates meeting the requirements of high efficiency stacked solar cells and optoelectronic devices where a certain bandgap is necessary. In this thesis to obtain reliable information about the native and light induced defect states present in a-SiGe:H alloy thin films of various germanium concentrations SSPC, DBP, transmission spectroscopy and PDS techniques have been used. A procedure based on Ritter Weiser optical formulation has been applied to calculate fringe free absolute absorption coefficient spectra of a-SiGe:H alloy thin films of various Ge% from the yield DBP and simultaneously measured transmission signals for the first time. The results have been compared with those independently measured by PDS method.In the annealed state the effects of native defect states in a-SiGe:H alloy thin films of various Ge% have been investigated. For the a-SiGe:H alloy films with Ge concentration in the range of 10% to 30%, hntn-products for the photogenerated free electrons is the highest, therefore they serve as the best photoconductive absorber layer in the multijunction solar cells. The effect of Ge content in amorphous silicon network clearly indicates a systematic decrease in the bandgap with increasing Ge content. The E0v values are almost constant around 55meV for alloying up to 40% Ge. Finally the changes in the defect density present in the bandgap of alloy films are inferred from the α(1.0eV) measured by both PDS and low bias light DBP spectrum. The difference between PDS and low bias DBP spectra is attributed to the underlying physics of these methods. The best film with lowest defect density can be prepared with alloying Ge in the range from 10% to 40% Ge.In the light soaked state, samples were left under white light illumination (15 suns) for determined time intervals. SSPC measurements indicate that all samples exhibit certain degree of degradation in the magnitude of sph and hntn products. The rate of α(1.0 eV) decreases as Ge% increases in the light soaked state. Higher Ge content films (50%, 75%) show almost no degradation in sub-bandgap absorption. As the degradation slope of α(hν) and 1/η nτn product are not same for all samples it can be inferred that subgap absorption and photoconductivity measurements are not controlled by the same set of defects present in the bandgap

Central vein sign: comparison of multiple sclerosis and leukoaraiosis

Background/aim: Leukoaraiosis produces white matter lesions (WML) similar to multiple sclerosis (MS) on brain magnetic resonance imaging (MRI), and the distinction between these two conditions is difficult radiologically. This study aimed to investigate the role of the central vein sign (CVS) in susceptibility-weighted imaging (SWI) sequence in distinguishing MS lesions from leukoaraiosis lesions in Turkish population. Materials and methods: In this prospective study, axial SWI and sagittal three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) were obtained in 374 consecutive patients. The study consisted of 169 (89 MS patients, 80 patients with leukoaraiosis) patients according to the inclusion and exclusion criteria. Two observers evaluated MR images by consensus, and observers were unaware of the patient’s clinical findings. Locations (periventricular, juxtacortical, and deep white matter) and the presence of CVS were investigated for each of the lesions. Differences between patients in the leukoaraiosis and MS groups were investigated using the Mann-Whitney U test or chi-square analysis. In addition, receiver operating characteristic (ROC) analysis was used to analyze the diagnostic performance of CVS. Results: A total of 1908 WMLs (1265 MS lesions, 643 leukoaraiosis) were detected in 169 patients. The CVS was significantly higher in the MS lesions (p < 0.001). The CVS positivity rate in periventricular WMLs was higher than in juxtacortical WMLs or deep WMLs, both for all patients and for patients with MS (p < 0.001). The area under the curve (AUC) of the ROC analysis was 0.88 (95% confidence interval 0.83–0.93) for CVS in the distinction of MS lesions and leukoaraiosis. Conclusion: The presence of CVS in the SWI sequence can be used as an auxiliary finding for the diagnosis of MS in the differentiation of MS and leukoaraiosis lesions. © TÜBİTAK

Vitrification of Common Carp (Cyprinus Carpio) Spermatozoa, Post-Thaw Sperm Quality, and Fertility

The aim of this investigation was to test a new technology, vitrification, or ultra-rapid freezing of the spermatozoa of common carp, and to study the ability of glucose, BSA, and other cryoprotectants to protect these cells from cryo-injuries. Spermatozoa were isolated and vitrified using 10 different cryoprotectant solutions: (1) Glucose based medium (GBM) + 1% bovine serum albumin (BSA); (2) GBM + 1% BSA + 10% DMSO; (3) GBM + 1% BSA + 20% DMSO; (4) GBM + 1% BSA + 30% DMSO; (5) GBM + 1% BSA + 10% DMA; (6) GBM + 1% BSA + 20% DMA; (7) GBM + 1% BSA + 30% DMA; (8) GBM + 1% BSA + 10% methanol; (9) GBM + 1% BSA + 20% methanol; (10) GBM + 1% BSA + 30% methanol. Fertilization rates for vitrification experiments were low and the use of low concentrations of cryoprotectants yielded lower fertilization rates than the vitrification solutions containing high cryoprotectant concentrations. In conclusion, this study reported successful vitrification of common carp spermatozoa by direct transfer into liquid nitrogen

Genotoxic effects of boric acid and borax in zebrafish, Danio rerio using alkaline comet assay

The present study is conducted to determine the potential mechanisms of Boron compounds, boric acid (BA) and borax (BX), on genotoxicity of zebrafish Danio rerio for 24, 48, 72 and 96-hours acute exposure (level:1, 4, 16, 64 mg/l BA and BX) in semi-static bioassay experiment. For that purpose, peripheral erythrocytes were drawn from caudal vein and Comet assay was applied to assess genotoxicity. Acute (96 hours) exposure and high concentrations of boric acid and borax increases % tail DNA and Olive tail moment. Genotoxicity was found for BA as concentration-dependent and BX as concentration and time dependent manner. In general, significant effects (P < 0,05) on both concentrations and exposure times were observed in experimental groups. DNA damage was highest at 96 h and 24 h for all BX and BA concentrations, respectively in peripheral blood of D. rerio. For the first time, our study demonstrates the effect of waterborne BA and BX exposure on genotoxicity at the molecular level, which may contribute to understanding the mechanism of boric acid and borax-induced genotoxicity in fish