634 research outputs found

    Unified traction and battery charging systems for electric vehicles: a sustainability perspective

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    This paper presents an analysis of unified traction and battery charging systems for electric vehicles (EVs), both in terms of operation modes and in terms of implementation cost, when compared to dedicated solutions that perform the same operation modes. Regarding the connection of the EV battery charging system with the power grid, four operation modes are analyzed: (1) Grid–to–Vehicle (G2V); (2) Vehicle–to–Grid (V2G); (3) Vehicle–to–Home (V2H); and (4) Vehicle–for–Grid (V4G). With an EV unified system, each of these operation modes can be used in single–phase and three–phase power grids. Furthermore, a cost estimation is performed for an EV unified system and for dedicated systems that can perform the same functionalities, in order to prove the benefits of the EV unified approach. The cost estimation comprises two power levels, namely 6 kW, single–phase, related to domestic installations, and 50 kW, three–phase, related to industrial installations. The relevance of unified traction and battery charging systems for EVs is proven for single–phase and three–phase power grids.This work has been supported by FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2019. This work has been supported by the FCT Project DAIPESEV PTDC/EEI-EEE/30382/2017, and by the FCT Project new ERA4GRIDs PTDC/EEI-EEE/30283/2017

    HyPLC: Hybrid Programmable Logic Controller Program Translation for Verification

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    Programmable Logic Controllers (PLCs) provide a prominent choice of implementation platform for safety-critical industrial control systems. Formal verification provides ways of establishing correctness guarantees, which can be quite important for such safety-critical applications. But since PLC code does not include an analytic model of the system plant, their verification is limited to discrete properties. In this paper, we, thus, start the other way around with hybrid programs that include continuous plant models in addition to discrete control algorithms. Even deep correctness properties of hybrid programs can be formally verified in the theorem prover KeYmaera X that implements differential dynamic logic, dL, for hybrid programs. After verifying the hybrid program, we now present an approach for translating hybrid programs into PLC code. The new tool, HyPLC, implements this translation of discrete control code of verified hybrid program models to PLC controller code and, vice versa, the translation of existing PLC code into the discrete control actions for a hybrid program given an additional input of the continuous dynamics of the system to be verified. This approach allows for the generation of real controller code while preserving, by compilation, the correctness of a valid and verified hybrid program. PLCs are common cyber-physical interfaces for safety-critical industrial control applications, and HyPLC serves as a pragmatic tool for bridging formal verification of complex cyber-physical systems at the algorithmic level of hybrid programs with the execution layer of concrete PLC implementations.Comment: 13 pages, 9 figures. ICCPS 201

    Development of a Multidisciplinary Program to Expedite Care of Esophageal Emergencies

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    Background Level 1 programs have improved outcomes by expediting the multidisciplinary care of critically ill patients. We established a novel level 1 program for the management of esophageal emergencies. Methods After institutional review board approval, we performed a retrospective analysis of patients referred to our level 1 esophageal emergency program from April 2013 through November 2015. A historical comparison group of patients treated for the same diagnosis in the previous 2 years was used. Results Eighty patients were referred and transported an average distance of 56 miles (range, 1–163 miles). Median time from referral to arrival was 2.4 hours (range, 0.4-12.9 hours). Referrals included 6 (7%) patients with esophageal obstruction and 71 (89%) patients with suspected esophageal perforation. Of the patients with suspected esophageal perforation, causes included iatrogenic (n = 26), Boerhaave’s syndrome (n = 32), and other (n = 13). Forty-six percent (n = 33) of patients were referred because of pneumomediastinum, but perforation could not be subsequently demonstrated. Initial management of patients with documented esophageal perforation included operative treatment (n = 25), endoscopic intervention (n = 8), and supportive care (n = 5). Retrospective analysis demonstrated a statistically significant difference in mean Pittsburgh severity index score (PSS) between esophageal perforation treatment groups (p < 0.01). In patients with confirmed perforations, there were 3 (8%) mortalities within 30 days. More patients in the esophageal level 1 program were transferred to our institution in less than 24 hours after diagnosis than in the historical comparison group (p < 0.01). Conclusions Development of an esophageal emergency referral program has facilitated multidisciplinary care at a high-volume institution, and early outcomes appear favorable

    Impact of the development of an endoscopic eradication program for Barrett's esophagus with high grade dysplasia or early adenocarcinoma on the frequency of surgery

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    Background and aims  The impact of the advent of an institutional endoscopic eradication therapy (EET) program on surgical practice for Barrett's esophagus (BE)-associated high grade dysplasia (HGD) or suspected T1a esophageal adenocarcinoma (EAC) is unknown. The aims of this study are to evaluate the different endoscopic modalities used during development of our EET program and factors associated with the use of EET or surgery for these patients after its development. Methods  Patients who underwent primary endoscopic or surgical treatment for BE-HGD or early EAC at our hospital between January 1992 and December 2014 were retrospectively identified. They were categorized by their initial modality of treatment during the first year, and the impact over time for choice of therapy was assessed by multivariable logistic regression. Results  We identified 386 patients and 80 patients who underwent EET and surgery, respectively. EET included single modality therapy in 254 (66 %) patients and multimodal therapy in 132 (34 %) patients. Multivariable logistic regression showed that, for each subsequent study year, EET was more likely to be performed in patients who were older ( P  = 0.0009), with shorter BE lengths ( P  < 0.0001), and with a pretreatment diagnosis of HGD ( P  = 0.0054) compared to surgical patients. The diagnosis of EAC did not increase the utilization of EET compared to surgery as time progressed ( P  = 0.8165). Conclusion  The introduction of an EET program at our hospital increased the odds of utilizing EET versus surgery over time for initial treatment of patients who were older, had shorter BE lengths or the diagnosis of BE-HGD, but not in patients with EAC

    Multidisciplinary clinic approach improves overall survival outcomes of patients with metastatic germ-cell tumors

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    Background To report our experience utilizing a multidisciplinary clinic (MDC) at Indiana University (IU) since the publication of the International Germ Cell Cancer Collaborative Group (IGCCCG), and to compare our overall survival (OS) to that of the National Cancer Institute (NCI) Surveillance, Epidemiology, and End Results (SEER) Program. Patients and methods We conducted a retrospective analysis of all patients with metastatic germ-cell tumor (GCT) seen at IU from 1998 to 2014. A total of 1611 consecutive patients were identified, of whom 704 patients received an initial evaluation by our MDC (including medical oncology, pathology, urology and thoracic surgery) and started first-line chemotherapy at IU. These 704 patients were eligible for analysis. All patients in this cohort were treated with cisplatin–etoposide-based combination chemotherapy. We compared the progression-free survival (PFS) and OS of patients treated at IU with that of the published IGCCCG cohort. OS of the IU testis cancer primary cohort (n = 622) was further compared with the SEER data of 1283 patients labeled with ‘distant’ disease. The Kaplan–Meier method was used to estimate PFS and OS. Results With a median follow-up of 4.4 years, patients with good, intermediate, and poor risk disease by IGCCCG criteria treated at IU had 5-year PFS of 90%, 84%, and 54% and 5-year OS of 97%, 92%, and 73%, respectively. The 5-year PFS for all patients in the IU cohort was 79% [95% confidence interval (CI) 76% to 82%]. The 5-year OS for the IU cohort was 90% (95% CI 87% to 92%). IU testis cohort had 5-year OS 94% (95% CI 91% to 96%) versus 75% (95% CI 73% to 78%) for the SEER ‘distant’ cohort between 2000 and 2014, P-value <0.0001. Conclusion The MDC approach to GCT at high-volume cancer center associated with improved OS outcomes in this contemporary dataset. OS is significantly higher in the IU cohort compared with the IGCCCG and SEER ‘distant’ cohort

    Integrated system for traction and battery charging of electric vehicles with universal interface to the power grid

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    This paper proposes an integrated system for traction and battery charging of electric vehicles (EVs) with universal interface to the power grid. In the proposed system, the power electronics converters comprising the traction drive system are also used for the battery charging system, reducing the required hardware, meaning the integrated characteristic of the system. Besides, this interface is universal, since it can be performed with the three main types of power grids, namely: (1) Single-phase AC power grids; (2) Three-phase AC power grids; (3) DC power grids. In these three types of interfaces with the power grid, as well as in the traction drive operation mode, bidirectional operation is possible, framing the integration of this system into an EV in the context of smart grids. Moreover, the proposed system endows an EV with an on-board fast battery charger, whose operation allows either fast or slow battery charging. The main contributes of the proposed system are detailed in the paper, and simulation results are presented in order to attain the feasibility of the proposed system.This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT -Fundacao para a Ciencia e Tecnologia within the Project Scope: UID/CEC/00319/2013. This work has been supported by FCT within the Project Scope DAIPESEV - Development of Advanced Integrated Power Electronic Systems for Electric Vehicles: PTDC/EEI-EEE/30382/2017. Mr. Tiago Sousa is supported by the doctoral scholarship SFRH/BD/134353/2017 granted by the Portuguese FCT agency. This work is part of the FCT project 0302836 NORTE-01-0145-FEDER-030283

    Sport fans' roles in value co-creation

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    Research question The sports industry has witnessed sustained growth. The cultural, symbolic and stakeholder-embedded nature of sport provides a dynamic setting for developing service research. In this context, an evolution in the logic of value creation can be observed; fans are no longer passive receivers of value but, instead, can be active value co-creators. The sport fan exhibits distinctive characteristics and an ability and willingness to integrate resources and co-produce value propositions, which necessitates an understanding of fan value co-creation. We answer one key research question: what is the role of fans in value co-creation in sports? We do so by conceptually exploring the processes through which sport fans co-create and provide value propositions. Research methods We use case exemplars to provide a base for the theoretical consideration of the role of sport fans in value co-creation. We verify and consolidate the service-dominant logic (SDL) in the sport context. However, due to the high level of abstraction of the SDL as a general theory, we utilize consumer culture theory (CCT) as a middle range theory (MRT) to bridge the gap between contextual descriptions of the role of fans and the SDL. Results and findings Fans evaluate, redefine and reposition value propositions in different sport settings. The three roles of assimilators, adaptors and authenticators in value co-creation are identified through five case exemplars. We extend the theoretical understanding of the processes through which sport fans co-create value. Implications Knowledge of the distinctive characteristics of sport fans and their roles in value co-creation will assist managers in developing effective marketing propositions. Our theoretical contribution will generate new lines of research in the field

    The Influence of Airway Closure Technique for Right Pneumonectomy on Wall Tension During Positive Pressure Ventilation: An Experimental Study

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    Bronchopleural fistula (BPF) remains a significant source of morbidity and mortality after right pneumonectomy (RPN). Postoperative mechanical ventilation represents a primary risk factor for BPF. We undertook an experiment to determine the influence of airway diameter on suture line tension during mechanical ventilation after RPN. RPN was performed in 6 fresh human adult cadavers. After initial standard bronchial stump closure (BSC), the airway suture lines were subjected to 5 cm H2O incremental increases in airway pressures beginning at 5–40 cm H2O. To minimize airway diameter, a carinal resection was then performed with trachea to left main bronchial anastomosis and the airway suture lines subjected to similar incremental airway pressures. Wall tension (N/m) at the suture lines was measured using piezoresistive sensors at each pressure point. As delivered airway pressure increased, there was a concomitant increase in wall tension after BSC and carinal resection. At every point of incremental positive pressure, wall tension was however significantly lower after carinal resection when compared to BSC (P < 0.05). Additionally the differences in airway tension became even more significant with higher delivered airway pressure (P < 0.001). Airway diverticulum after BSC leads to significantly increased tension on the bronchial closure with positive airway pressure as compared to a closure which minimize airway diameter after RPN. This supports the role of Laplacian Law where small increases in airway diameter result in significant increases on closure site tension. Techniques which reduce airway diameter at the airway closure will more reliably reduce the incidence of BPF following RPN
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