Μέθοδοι σταθρεοποίησης με ανάδραση για την επίλυση προβλημάτων μη γραμμικού προγραμματισμού

Εθνικό Μετσόβιο Πολυτεχνείο--Μεταπτυχιακή Εργασία. Διεπιστημονικό-Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.) “Μαθηματική Προτυποποίηση σε Σύγχρονες Τεχνολογίες στην Οικονομία

Accelerating Spatio-Textual Queries with Learned Indices

Efficiently computing spatio-textual queries has become increasingly important in various applications that need to quickly retrieve geolocated entities associated with textual information, such as in location-based services and social networks. To accelerate such queries, several works have proposed combining spatial and textual indices into hybrid index structures. Recently, the novel idea of replacing traditional indices with ML models has attracted a lot of attention. This includes works on learned spatial indices, where the main challenge is to address the lack of a total ordering among objects in a multidimensional space. In this work, we investigate how to extend this novel type of index design to the case of spatio-textual data. We study different design choices, based on either loose or tight coupling between the spatial and textual part, as well as a hybrid index that combines a traditional and a learned component. We also perform an experimental evaluation using several real-world datasets to assess the potential benefits of using a learned index for evaluating spatio-textual queries

Towards personalized services in the healthcare domain

Healthcare services are designed for enabling the provision of medical care to the patient. The traditional healthcare services are based on the doctor-centric paradigm. Essentially, they enable healthcare providers to assess patients’ health status based on information derived from medical examination and information stored in patient’s electronic Medical Health Records (eMHRs) [1]. Hence, it is crucial for patient’s health data to be digitalized and organized in such a way allowing their exploitation by the healthcare provider at a later point of time [2]. The doctor-centric healthcare services enhance healthcare providers’ diagnosing skills and enable them to give patients accurate treatment directions aiming to their earlier and safer de-hospitalization

Provision of Personalized Ubiquitous Healthcare Services over NGN Using Always Best Connected Service Provider

This paper presents a personalized middleware for mobile eHealth (mHealth) services for use in the Ubiquitous Consumer Wireless World (UCWW). The middleware was developed based on the ISO/IEEE 11073 personal health data (PHD) standards. It works as a multi-agent system (MAS) to provide intelligent collection of physiological data from medical sensors attached to human body, and subsequent sending of gathered data to a log data node by utilizing the Always Best Connected and best Served (ABC&S) communication paradigm. A number of design issues associated with the middleware implementation are outlined

Roll-to-Roll Fabrication of Bijels via Solvent Transfer Induced Phase Separation (R2R-STrIPS)

Bicontinuous interfacially jammed emulsion gels (bijels) are soft materials with applications in separation science, energy storage, catalysis, and tissue engineering. Bijels are formed by arresting the liquid–liquid phase separation of two immiscible liquids via interfacial jamming of colloidal particles. Current fabrication methods of bijels employ either batch processing or continuous-flow microfluidic synthesis. Production methods with higher throughput are needed to facilitate large-scale synthesis of bijels. Herein, it is shown that roll-to-roll processing (R2R) enables the fabrication of bijel films with controlled dimensions at rates of several cm3 per minute. Increasing the bijel production rate via R2R requires an understanding of the interaction of the bijel with the R2R substrate. The study demonstrates that controlling the wetting on the R2R substrate enables the synthesis of uniform bijel films with adjustable thickness. Moreover, this research shows that the bijel film microstructure depends on the mechanism of phase separation and particle surface functionalization. The resulting knowledge gains can help to leverage bijel synthesis from laboratory to industrial scales in the future, promoting the exciting application potentials of bijels

Laparoscopic vs Open approach for transverse colon cancer. A systematic review and meta-analysis of short and long term outcomes

Background: Transverse colon malignancies have been excluded from all randomized controlled trials comparing laparoscopic against open colectomies, potentially due to the advanced laparoscopic skills required for dissecting around the middle colic vessels and the associated morbidity. Concerns have been expressed that the laparospopic approach may compromise the oncological clearance in transverse colon cancer. This study aimed to comprehensively compare the laparoscopic (LPA) to the open (OPA) approach by performing a meta-analysis of long and short term outcomes. Methods: Medline, Embase, Cochrane library, Scopus and Web of Knowledge databases were interrogated. Selected studies were critically appraised and the short-term morbidity and long term oncological outcomes were meta-analyzed. Sensitivity analysis according to the quality of the study, type of procedure (laparoscopic vs laparoscopically assisted) and level of lymphadenectomy was performed. Statistical heterogeneity and publication bias were also investigated. Results: Eleven case control trials (1415 patients) were included in the study. There was no difference between the LPA and the OPA in overall survival [Hazard Ratio (HR)=0.83 (0.56, 1.22); P=0.34], disease free survival (p=0.20), local recurrence (p=0.81) or distant metastases (p=0.24). LPA was found to have longer operative time [Weighted mean difference (WMD)=45.00 (29.48, 60.52);P<0.00001] with earlier establishment of oral intake [WMD=-1.68 (-1.84, -1.53);P<0.00001] and shorter hospital stay [WMD =-2.94 (-4.27, -1.62);P=0.0001]. No difference was found in relation to anastomotic leakage (p=0.39), intra-abdominal abscess (p=0.25), lymph nodes harvested (p=0.17). Conclusions: LPA seems to be safe with equivalent oncological outcomes to OPA and better short term outcomes in selected patient populations. High quality Randomized control trials are required to further investigate the role of laparoscopy in transverse colon cancer

Outbreak of West Nile Virus Infection in Greece, 2010

During 2010, an outbreak of West Nile virus infection occurred in Greece. A total of 197 patients with neuroinvasive disease were reported, of whom 33 (17%) died. Advanced age and a history of heart disease were independently associated with death, emphasizing the need for prevention of this infection in persons with these risk factors