21 research outputs found
Enabling instant- and interval-based semantics in multidimensional data models: the T+MultiDim Model
Time is a vital facet of every human activity. Data warehouses, which are huge repositories of historical information, must provide analysts with rich mechanisms for managing the temporal aspects of information. In this paper, we (i) propose T+MultiDim, a multidimensional conceptual data model enabling both instant- and interval-based semantics over temporal dimensions, and (ii) provide suitable OLAP (On-Line Analytical Processing) operators for querying temporal information. T+MultiDim allows one to design typical concepts of a data warehouse including temporal dimensions, and provides one with the new possibility of conceptually connecting different temporal dimensions for exploiting temporally aggregated data. The proposed approach allows one to specify and to evaluate powerful OLAP queries over information from data warehouses. In particular, we define a set of OLAP operators to deal with interval-based temporal data. Such operators allow the user to derive new measure values associated to different intervals/instants, according to different temporal semantics. Moreover, we propose and discuss through examples from the healthcare domain the SQL specification of all the temporal OLAP operators we define. (C) 2019 Elsevier Inc. All rights reserved
Radio-over-modes for C-RAN architecture with smart optical resources assignment
In this paper we consider a centralized radio access network (C-RAN) architecture with a fully analog fronthaul link between remote radio heads (RRHs) and baseband units (BBUs) based on the radio over fiber (RoF) paradigm. Mode division multiplexing (MDM) and frequency division multiplexing (FDM) are employed to provide an additional multiplexing signal dimension to meet the huge bandwidth requirements of next generation (5G) wireless mobile systems. The main contribution of the paper is to prove that a smart resource assignment between the radio antennas and the mode/frequency dimensions allows the communication over the RRH-BBU link at rates that are comparable to those achieved by an ideal fronthauling where BBU and RRH are assumed to be co-located, even without any complex and costly optical equalization technique. Validation is on the radio-link capabilities employing multiple antennas to meet the demand for massive MIMO technology
Hinged external fixation for Regan-Morrey type I and II fractures and fracture-dislocations
Elbow fracture-dislocation is always demanding to manage due to the considerable soft-tissue swelling or damage involved, which can make an early open approach and ligamentous reconstruction impossible. The purpose of this study was to evaluate the role of elbow hinged external fixation (HEF) as a definitive treatment in patients with elbow dislocations associated with Regan–Morrey (R-M) type I and II coronoid fractures and soft-tissue damage. We treated 11 patients between 2010 and 2012 with HEF. Instability tests and standard X-ray examinations were performed before surgery and 1–3 to 3–6 months after surgery, respectively. All patients underwent a preoperative CT scan. Outcomes were assessed with a functional assessment scale (Mayo Elbow Performance Score, MEPS) that included 4 parameters: pain, ROM, stability, and function. The results were good or excellent in all 11 patients, and no patient complained of residual instability. Radiographic examination showed bone metaplasia involving the anterior and medial sides of the joint in 5 patients. HEF presented several advantages: it improves elbow stability and it avoids long and demanding surgery in particular in cases with large soft tissue damage. We therefore consider elbow HEF to be a viable option for treating R-M type I and II fracture-dislocations
Formal and conceptual modeling of spatio-temporal granularities
In the database research field the management of temporal and spatial information is crucial. Many information may be temporally and spatially qualified, i.e., data may be associated to temporal and spatial locations. In the management of qualified data, the notion of \u201cgranularity\u201d plays an important role; it allows one to reason about temporal and spatial data expressed with different units of measure. By merging together notions of temporal and spatial granularity, in this work we present a formal framework for the representation and management of spatio-temporal granularities. This framework includes relationships and operations between granularities. Moreover, we propose a conceptual design allowing us to represent temporal, spatial, and spatio-temporal granularities in a relational
database
An OLAP-based approach to modeling and querying granular temporal trends
Data warehouses contain valuable information for decision-making purposes, they can be queried and visualised with Online Analytical Processing (OLAP) tools. They contain time-related information and thus representing and reasoning on temporal data is important both to guarantee the efficacy and the quality of decision-making processes, and to detect any emergency situation as soon as possible. Several proposals deal with temporal data models and query languages for data warehouses, allowing one to use different time granularities both when storing and when querying data. In this paper we focus on two aspects pertaining to temporal data in data warehouses, namely, temporal patterns and temporal granularities. We first motivate the need for discovering granular trends in an OLAP context. Then, we propose a model for analyzing granular temporal trends in time series by taking advantage of the hierarchical structure of the time dimension. © 2014 Springer International Publishing.SCOPUS: cp.kinfo:eu-repo/semantics/publishe
Platelet-rich plasma in the treatment of acute hamstring injuries in professional football players
muscle injuries have a high incidence in professional football and are responsible for the largest number of days lost from competition. Several in vitro studies have confirmed the positive role of platelet-rich plasma (PRP) in accelerating recovery and in promoting muscle regeneration, and not fibrosis, in the healing process. This study examines the results of intralesional administration of PRP in the treatment of primary hamstring injuries sustained by players belonging to a major league football club
A geographic, multimedia and temporal data model for semistructured data
The paper proposes a model for the representation of spatio-temporal information with a semistructured approac
Return to sport after ACL reconstruction: a survey between the Italian Society of Knee, Arthroscopy, Sport, Cartilage and Orthopaedic Technologies (SIGASCOT) members
Background: A worldwide consensus for timing and criteria for return to sport after anterior cruciate ligament (ACL) reconstruction is lacking. The aim of the study was to survey among the Italian Society of Knee, Arthroscopy, Sport, Cartilage and Orthopaedic Technologies (SIGASCOT) members in order to evaluate their approaches to the return to sport after ACL reconstruction regarding timing and criteria. Methods: A web survey among the SIGASCOT members was performed, including 14 questions regarding technical and graft preferences, timing for return to training and competitive activity for contact and non-contact sports and criteria to allow return to sport. Results: Totally, 123 members completed the questionnaire. Return to training sports was allowed within 6\ua0month by 87\ua0% for non-contact sports and by 53\ua0% for contact sports. Return to competitive activity was allowed within 6\ua0months by 48\ua0% for non-contact sports and by 13\ua0% for contact sports. Full ROM (77\ua0%), Lachman test (65\ua0%) and Pivot-Shift test (65\ua0%) were the most used criteria to allow return to sport. The 90\ua0% used at least one clinical score. Conclusion: The SIGASCOT members showed various approaches in the return to sport after ACL reconstruction, with differences between return to training or competitive activity, and between contact and non-contact sports. Six months was generally considered adequate by most of the members for the most demanding activities. The most used criteria to allow return to sport were manual testing. A clear definition of sport activities and more objective criteria for the return to sport are needed. Level of evidence: Level V, expert opinion
Optical multilevel pulsewidth modulation for analog mobile fronthaul
The evolution of radio access networks is towards a centralized architecture (C-RAN), with massive antenna deployments and large radio-frequency bandwidths. In the next future, traditional optical transport technologies based on digital radio over fiber will no longer be able to support the mobile fronthaul traffic connecting antennas hosted at remote radio units and centralized baseband units. Analog radio over fiber can be selected to support the mobile fronthaul (MFH) network and, in particular, pulse width modulation (PWM) is a viable alternative for analog signal transport. In order to increase the MFH spectral efficiency, we propose to exploit multilevel PWM (M-PWM) in a wavelength division multiplexing-passive optical network (WDM-PON) network, comparing its performance with a conventional 2-level PWM solution. Experimental results show successful transmission over 7.5-km standard single mode fiber (SSMF) of up to 16 aggregated LTE-like 20-MHz signals with 64-QAM on each subcarrier, while up to eight aggregated LTE-like 20-MHz signals with 256-QAM could be supported. M-PWM thus allows either using higher order modulation formats or aggregating a higher number of LTE channels