Polyhedral Properties of RLT Relaxations of Nonconvex Quadratic Programs and Their Implications on Exact Relaxations

We study linear programming relaxations of nonconvex quadratic programs given by the reformulation-linearization technique (RLT), referred to as RLT relaxations. We investigate the relations between the polyhedral properties of the feasible regions of a quadratic program and its RLT relaxation. We establish various connections between recession directions, boundedness, and vertices of the two feasible regions. Using these properties, we present necessary and sufficient exactness conditions for RLT relaxations. We then give a thorough discussion of how our results can be converted into simple algorithmic procedures to construct instances of quadratic programs with exact, inexact, or unbounded RLT relaxations.Comment: Technical Report, School of Mathematics, The University of Edinburgh, Edinburgh, EH9 3FD, Scotland, United Kingdo

Fast and accurate mosaicing techniques for aerial images of quasi-planar scenes

Image mosaicing aims to increase visual perception by composing data from separate images since a mosaic image provides a more powerful scene description. Gaining and maintaining situational awareness from image mosaics is important for both civil and military applications. Inspection of the urban areas suffering from natural disasters and examination of the large plantations are possible civil areas of utilization. For military applications, image mosaicing can provide critical information about enemy activities in wide areas. Although there are many studies in the literature that focus on creating real-time image mosaics for different applications, there is still room for improvement due to the need for faster and more accurate mosaicing for a variety of practical scenarios. In this thesis, novel techniques for creating fast and accurate aerial image mosaics of quasi-planar scenes are developed. First, a sequential mosaicing approach is proposed where all the past images intersecting the new image are used to estimate alignment of the new image. A tool from computer graphics, Separating Axis Theorem (SAT), is employed to detect image intersections. A new local affine refinement is introduced to provide global consistency throughout the mosaic. Second, a pose estimation based mosaicing technique is developed where the scene normal and the camera pose parameters are estimated through an Extended Kalman Filter (EKF). Mosaic is formed by using the homographies constructed from the estimated state vector. Using an EKF based approach provides a significant global consistency throughout the mosaic since all the parameters are updated by which error accumulations in the loop closing regions are compensated. Proposed algorithm also provides localization and attitude information of the camera which might be beneficial for robotics applications. Both methods are verified through several experiments and comparisons with some state-of-the-art algorithms are presented. Results show that the developed algorithms work successfully as intended

On Tractable Convex Relaxations of Standard Quadratic Optimization Problems under Sparsity Constraints

Standard quadratic optimization problems (StQPs) provide a versatile modelling tool in various applications. In this paper, we consider StQPs with a hard sparsity constraint, referred to as sparse StQPs. We focus on various tractable convex relaxations of sparse StQPs arising from a mixed-binary quadratic formulation, namely, the linear optimization relaxation given by the reformulation-linearization technique, the Shor relaxation, and the relaxation resulting from their combination. We establish several structural properties of these relaxations in relation to the corresponding relaxations of StQPs without any sparsity constraints, and pay particular attention to the rank-one feasible solutions retained by these relaxations. We then utilize these relations to establish several results about the quality of the lower bounds arising from different relaxations. We also present several conditions that ensure the exactness of each relaxation.Comment: Technical Report, School of Mathematics, The University of Edinburgh, Edinburgh, EH9 3FD, Scotland, United Kingdo

Recovery of tinnitus and sensorineural hearing loss due to lysis of arachnoid adhesions in the posterior cranial fossa: Is there a novel etiology in neurotological disorders?

WOS: 000408247500032PubMed ID: 28816700We reported the recovery of sensorineural hearing loss and tinnitus in a 22-year-old man after complete removal of intracranial portion of jugular foramen schwannoma via the retrosigmoid approach. The aim of this case report was to present the excision of a large jugular foramen schwannoma via the retrosigmoid approach and to describe the improvement of sensorineural hearing loss related to arachnoid inflammations due to chronic arachnoiditis after suboccipital craniectomy. The recovery of sensorineural hearing loss and tinnitus after release of arachnoid adhesions may indicate the clinical significance of these adhesions or arachnoiditis, which should also be considered and investigated in the etiology of other neurotological diseases

A modular software architecture for UAVs

There have been several attempts to create scalable and hardware independent software architectures for Unmanned Aerial Vehicles (UAV). In this work, we propose an onboard architecture for UAVs where hardware abstraction, data storage and communication between modules are efficiently maintained. All processing and software development is done on the UAV while state and mission status of the UAV is monitored from a ground station. The architecture also allows rapid development of mission-specific third party applications on the vehicle with the help of the core module

The effect of systemic therapies on hemogram parameters and C-reactive protein in patients with psoriatic arthritis

Background and Design: Although some inflammatory markers were elevated in patients with psoriatic arthritis (PsA) compared to healthy controls, are few studies evaluated the effects of systemic treatments for PsA on these markers. The aim of this study is to investigate the changes in hemogram parameters and C-reactive protein (CRP) in PsA patients receiving systemic therapies. Materials and Methods: In this retrospective study, hemogram parameters, CRP, and systemic inflammation indices [neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio, systemic immune-inflammation index (SII), and systemic inflammation response index (SIRI)] of 50 PsA patients were analyzed before and in the third month of the treatments. Results: While mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and hemoglobin (Hb) were higher in the third month of all treatments compared to the baseline (p=0.009, 0.003, and 0.036, respectively), platelet, CRP and SII were lower (p=0.001, 0.000, and 0.000, respectively). In the biological therapy group (n=21), platelet, SIRI, and SII were lower, while MCHC was higher in the third month than baseline (p=0.023, 0.033, 0.000, and 0.003, respectively). CRP and SII were lower in the third month of the non-biologic treatment group (n=29) compared to the baseline, and MCH and mean corpuscular volume (MCV) were higher (p=0.001, 0.000, 0.027, and 0.044, respectively). No statistically different changes were recorded in NLR, PLR, and other parameters. Conclusion: Hb, MCH, and MCHC increased, and platelet, CRP, and SII decreased in the third month of all systemic therapies. MCV was higher in the non-biologic treatment group, and SIRI was lower in the biological treatment group in the third month than baseline. Therefore, these parameters may be useful for monitoring the effects of treatments in PsA

Outcomes for revision total knee replacement after unicompartmental knee replacement

Objective: The aim of this retrospective, observational study was to describe the outcomes of total knee replacement (TKR) after failed Oxford phase 3 medial unicompartmental knee replacement (UKR). Methods: The study included 24 revision TKRs (20 females, 4 males; mean age: 61 years) performed following failed aseptic UKR. Outcomes were assessed using the Knee Society Score (KSS). Results: The most common causes for revision were mobile bearing dislocation and unexplained pain. Mean preoperative KSS was 50.3 (range: 37 to 66) and 82.2 (range: 58 to 97) after TKR. There were 17 excellent, 4 good, 2 fair and 1 poor results. Conclusion: The type of UKR performed (cemented versus uncemented) had no effect on TKR success. Revision for failed UKR with TKR appears to be a technically straightforward procedure with satisfactory early clinical results

Extragenital endometriosis (a case report)

Endometriozis is rarely seen on incisional scars following a hernia operation, a incisional mass is considered to be either due to inflamation or reccurence. Preoperative diagnosis is diffucult and a definite diagnosis can only be made by an operative procedure and histopathological examination.İnsizyon skarlarında endometriozis oluşumu nadir görülmektedir. Fıtık ameliyatı sonrası, ameliyat lojunda kitle tespiti öncelikle inflamasyon yada fıtık nüksünü düşündürmektedir. Preoperatif tanı güç olup kesin tanı cerrahi girişim ve histopatolojik incelemeyle konulabilmektedir

Lisansüstü Öğretimin Sorunları Konusunda Ankara’daki Üniversitelerin Lisansüstü Enstitü Yöneticilerinin Görüşleri

The purpose of this research is to find out the opinions of the managers of the Postgraduate Education Institutes of State and Foundation Universities in Ankara on the Problems of Postgraduate Education. A research survey method, which enables to determine givens of the present situation, is used in the research. The data collection tool has been given to the managers of the Postgraduate Education Institutes (74) and 43 of them have submitted their answers back to us. Frequencies of the personal information about the participants have been taken, participation level of the managers on the descriptions about the problems of Postgraduate Education has been determined and described for every item, and are shown in frequencies and percentages.Araştırmanın amacı, lisansüstü öğretimin sorunları konusunda Ankara’daki devlet ve vakıf üniversitelerinin lisansüstü enstitü yöneticilerinin görüşlerini belirlemektir. Bu araştırmada, var olan durumu değerlendirme olanağı veren tarama modeli kullanılmıştır. Veri toplama aracı, Ankara’daki tüm lisansüstü öğretim yapan enstitü yöneticilerine (74) verilmiş, 43’ünden geri alınmıştır. Araştırmaya katılanlara ilişkin kişisel bilgilerin frekansları alınmış, lisansüstü öğretimin sorunları konusundaki ifadelere enstitü yöneticilerinin katılma düzeyi her maddeye ilişkin frekanslar ve yüzdeler bulunarak betimlenmiştir

Polyps of the gallbladder: retrospective analysis of 33 cases

Amaç: Safra kesesi polipleri , safra kesesi mukozasından köken alan lezyonlardır. Bu çalısmada, klinigimizde preoperatif safra kesesi polibi tanısı alarak cerrahi girisim uygulanan olgular patolojik tanıları ile tartısılmakta ve cerrahi endikasyon koyduracak kriterlerin tanımlanması amaçlanmaktadır. Materyal-Metod: Klinigimizde Ocak 1995 ile Haziran 2003 tarihleri arasında preopeeratif safra kesesi polibi tanısı alan olgular demografik özellikleri, klinik ve abdominal ultrasonografi bulguları, yapılan cerrahi tedavi, histopatolojik tanıları, morbidite ve mortalite açısından retrospektif olarak degerlendirildi. Bulgular: Kolesistektomi yapılan 1420 olgunun otuzüçü de (%2,3) preoperatif safra kesesi polibi tanısı almıstır. Karın agrısı en sık rastlanılan semptom idi.Tüm olgulara abdominal ultrasonografi ile tanı konulmus olup görüntülemede, 3 olguda sesil, 30 olguda ise pediküllü polip bulunurken, 7 olguda ek olarak kolelithiasis saptandı. Tedavide 8 olguda laparoskopik, 25 olguda ise açık olarak kolesistektomi yapıldı. Histopatolojik incelemede ; 16 olguda sadece kolelithiasis ve kronik kolesistit, 14 olguda kolesterol polibi, 2 olguda adenomatöz polip, 1 olguda ise adenokarsinom saptandı. Sonuç: Safra kesesi poliplerinde cerrahi tedavi, tüm semptomatik, beraberinde kolelitiasis olan, polip boyutu 10 mmgeçen ve ultrasonografik olarak malignite riski tasıyan olgularda yapılmalıdır.Aim: The nature of polypoid lesions of the gallbladder is difficult to define before operation, and surgical indications still remain controversial. The aim of this study was to identfy surgical indications for polypoid lesion of the gallbladder with regarding their ultrasonographic histopathological findings and indications. Material-Methods: Between 1995 and June 2003, the patients with preoperative diagnosis of gallbladder polyp were evaluated retrospectively according to their demographic findings, clinical symptoms, abdominal ultrasonography results, surgical treatment and pathology . Results: The incidence of preoperative gallbladder polyp diagnosis was 2,3% (33/1420) in cholecystectomized patients. The most common symptom was abdominal pain. In abdominal ultrasonography used for diagnosis in all patient, the polyps were sessile in 3 cases and pedunculated in 30 cases. Also cholelithiasis was coexist with polyp in 7 cases ultrasonographically. Cholecystectomy was made laparoscopically in 8 patients and others were with open technique. In histopathological assesment, the results were as only cholelithiasis and chronic cholecystitis / 16 cases, cholesterol polyp / 14 cases, adenoma / 2 cases and adenocarcinoma / 1 case. Conclusion: Surgery is the choice of treatment in all symptomatic patients and the cases having polyps with a size of greater than 10 mm as well as the cases carrying malignant features ultrasonographically