Analysis of Signature Generation Schemes for Multiterm Queries In Linear Hashing with Superimposed Signatures

Signature files provide efficient retrieval of data by reflecting the essence of the data objects into bit patterns. Our analysis explores the performance of three superimposed signature generation schemes as they are applied to a dynamic signature file organization based on linear hashing: Linear Hashing with Superimposed Signatures (LHSS). The first scheme (SM) allows all terms set the same number of bits whereas the second and third schemes (MMS aid MMM) emphasize the terms with high discriminatory power. In addition, MMM considers the probability distribution of the number of query terms. The main contribution of the study is a detailed analysis of LHSS in multiterm query environments by incorporating the term discrimination values based on document and query frequencies. The approach of the study can also be extended to other signature file access methods based on partitioning. The derivation of the performance evaluation formulas, the simulation results based on these formulas for various experimental settings, and the implementation results based on INSPEC and NPL text databases are provided. Results indicate that MMM and MMS outperform SM in all cases in terms of access savings, especially when terms become more distinctive. MMM slightly outperforms MMS in high weight and low weight query cases. The performance gap among all three schemes decreases as the database size increases, and as the signature size increases the performances of MMM and MMS decrease and converge to that of the SM scheme when the hashing level is fixed

A Study of Cache-Based IP Flow Switching

Meeting the service demands from QoS-based network applications is a very challenging task performed in many high-end routers and switches. This task involves management of resources like bandwidth and memory in network devices. The memory in the form of a very fast cache that instruments wire-speed classification, discrimination, and forwarding of network packets needs to be managed very effectively. We examine the management of a specific IP flow-cache architecture through simulations based on traffic traces collected from a campus intranet. A probabilistic cache install policy is examined over a range of cache sizes and install probabilities. This policy successfully identifies the flows that warrant caching and slightly improves deployable policies based on site-specific traffic information can increase the switching performance even higher

Integrating Physical Accessibility of Emergency Establishments into Earthquake Risk Assessment

Human being has always been in a continual struggle with disasters. They are mostly sudden and unexpected and cause irreversible damages to human life and property. Disasters are facts of life, but it is always possible to decrease the effects of disasters by preparedness. In disaster case, accessibility is one of the most vital and important components of disaster preparedness and mean the difference between loosing a life or saving a life. That is why emergency accessibility, regardless if it is measured in time, distance, population or any other cost, is the most important variable that decision makers must consider in the early stages of planning for developing planning policies. In the light of the above mentioned facts this study analyzed 3 different accessibility measurement techniques (Zone Based, Isochronal Based And Raster Based Techniques) within GIS environment for more efficient modeling of physical accessibility in Eskisehir urban area and for creating an accessibility vulnerability index as an input for a higher scale earthquake risk detection process. The results can also directly be used by emergency planners/city and regional planners as a part of a GIS based DSS (Decision Support System) in accessibility measurement or can be integrated into a more comprehensive disaster risk calculation processes

Endovascular treatment of acute type B dissection complicating graft-bypass repair for aortic coarctation

AbstractObjectivesThe early dissection of the descending aorta after the repair of aortic coarctation is very rare. Herein, we present a special endovascular technique used for acute type B dissection complicating graft bypass for aortic coarctation.MethodsThe 48 year-old male patient with the diagnosis of adult type aortic coarctation had bypass procedure between the aortic arch and the descending aorta. Six weeks after the first operation, the patient was readmitted with severe back pain and had the diagnosis of acute type B dissection which involved the descending aorta at the distal part of the graft anastomosis.ResultsTwo separate stent-grafts were deployed respectively 31 × 150 mm and 34 × 200 mm (C-TAG™ WL Gore&Asc., Flagstaff, AZ, USA). The previous Dacron bypass graft was used as a proximal landing zone for the first stent-graft. The distal landing zone for the second stent was the area between the celiac trunk and superior mesenteric artery. Therefore, the covered stent-graft was implanted to the celiac trunk (Viabahn™ 7 × 50 mm WL Gore&Asc, AZ, USA) to maintain its patency before the deployment of the second graft. The segment of coarctation was closed with a vascular plug (Amplatzer™ vascular plug II) to prevent persistent perfusion of aneurysmal false lumen.ConclusionThe endovascular approach offers multiple less invasive options based on a patient-specific problem

Agents in Network Management

The ubiquity and complexity of modern networks require automated management and control. With increases in scale, automated solutions based on simple data access models such as SNMP will give way to more distributed and algorithmic techniques. This article outlines present and near-term solutions based on the ideas of active networks and mobile agents, which permit sophisticated programmable control and management of ultra large scale networks

Okul öncesi öğretmen adaylarının epistemolojik inançları ile matematik öğretimi ve öğrenimine yönelik inançları

Araştırmanın amacı, okul öncesi eğitimdeki öğretmen adaylarının epistemolojik inançları ile matematik öğretimi, öğrenimi ve inançları arasındaki ilişkiyi belirlemek ve öğretmen adaylarının epistemolojik inançlarının, matematik öğretimi ve öğrenimine ilişkin inançlarını yordayıp yordamadığını araştırmaktır. Nicel araştırma kapsamında, ilişkisel tarama modeliyle tasarlanan araştırmanın çalışma grubu, İstanbul’daki beş üniversitenin okul öncesi eğitimi anabilim dalında öğrenim gören 248 son sınıf öğrencisidir. Araştırmada veri toplama araçları olarak “Epistemolojik İnançlar Ölçeği” ve “Matematik Öğretimi, Öğrenimi ve İnançlar Ölçeği” kullanılmıştır. Sonuçlar, okul öncesi öğretmen adaylarının epistemolojik inanç alt boyutlarından olan “öğrenme süreci- otorite/ uzman bilgisine şüphe” ve “öğrenme çabası” inanç düzeyleri artıkça matematik öğretimi ve öğrenimine ilişkin inanç düzeylerinin arttığını, öğretmen adaylarının “doğuştan/ sabit yetenek” ve “bilginin kesinliği” inanç düzeyi arttıkça, matematik öğretimi ve öğrenimine ilişkin inanç düzeylerinin azaldığını göstermiştir. Çalışma, öğretmen adaylarının “öğrenme süreci/uzman bilgisine şüphe” inancının matematik öğretimi ve öğrenimine ilişkin inançlarını pozitif olarak, “doğuştan/sabit yetenek” ve“bilginin kesinliği” inançlarını ise negatif olarak yordadığını göstermiştir

Coronary Angiography Utilization and Costs for Coronary Artery Bypass Graft Surgery Patients in Turkey

INTRODUCTION: To assess excess use of coronary angiography prior to coronary artery bypass graft surgery and its association with mortality, health care costs, and hospital quality in Turkey. METHODS: Using Turkish National Health Insurance Data (2009–2011) that included patients who underwent cardiac surgery, coronary angiography utilization was identified. Propensity score matching was used to compare survival rates and annual health care costs of patients in a coronary angiography excess-use group (>1 angiogram) and in a standard-therapy group (1 angiogram). The empirical Bayesian approach was used to combine mortality and hospital volume for quality index. The relationship between hospital quality and excess use of coronary angiography was assessed using Chi-squared tests. RESULTS: Out of 20,126 patients identified, 7.27% of patients underwent excessive coronary angiography procedures (excess-use group), with an average annual cost at 9.7% higher than those who had a single angiography (standard-therapy group; P < 0.01). Operational mortality associated with excessive use was significantly higher as well (7.4% versus 5.4%, P < 0.02). There exists variation in the use of coronary angiography across cities and hospitals. Patients who underwent cardiac surgery in high-quality hospitals were less likely to have excessive angiography use than those in low-quality hospitals (7.0% versus 9.5%, P < 0.01). CONCLUSION: In Turkey, excess use of coronary angiography prior to coronary artery bypass graft surgery is associated with higher operational mortality, higher expenditures, and lower hospital quality

Retrospective analysis of total direct medical costs associated with hepatitis B patients with oral antiviral versus pegylated interferon therapy in Turkey

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108669/1/jvh12206.pd

Appropriate image selection with virtual reality in vestibular rehabilitation: Cross-sectional study

Background: While vestibular rehabilitation with virtual reality (VR) is becoming more popular every day, the disadvantages of this method are not yet clear. Objective: The aim of this study is to examine the effect of the image to be used in vestibular rehabilitation with VR on the systems that provide body posture. Methods: The study was carried out with 36 participants (18 women and 18 men) aged 18 to 30 years. To assess balance control components separately, a sensory organization test was administered to the participants in the presence of stressful and relaxing environment images with VR technology. The State-Trait Anxiety Inventory survey was also used to measure the stress values in the created environments. Results: The State-Trait Anxiety Inventory survey revealed that while stressful videos significantly increased stress, relaxing videos reduced stress. Among measurements obtained in the presence of VR, significant decreases were observed mostly in the visual system data. A significant increase in vestibular system data (P=.01) was observed with a decrease in visual system data (P<.001) when the relaxing image was presented. Additionally, there was a significant difference in the somatosensory (P=.001), composite (P=.002), and visual system (P[removed

The Use of Total Artificial Heart With Example of Cases for End-Stage Heart Failure Therapy

29th Turkish Cardiology Congress of the Turkish-Society-of-Cardiology (TSC) with International Participation -- OCT 26-29, 2013 -- Antalya, TURKEYWOS: 000329858400098Turkish Soc Cardio