121 research outputs found
Connected Vehicles at Signalized Intersections: Traffic Signal Timing Estimation and Optimization
Summary: While traffic signals ensure safety of conflicting movements at intersections, they also cause much delay, wasted fuel, and tailpipe emissions. Frequent stops and goes induced by a series of traffic lights often frustrates passengers. However, the connectivity provided by connected vehicles applications can improve this situation. A uni-directional traffic signal to vehicle communication can be used to guide the connected vehicles to arrive at green which increases their energy efficiency; and in the first part of the dissertation, we propose a traffic signal phase and timing estimator as a complementary solution in situations where timing information is not available directly from traffic signals or a city’s Traffic Management Center. Another approach for improving the intersection flow is optimizing the timing of traditional traffic signals informed by uni-directional communication from connected vehicles. Nevertheless, one can expect further increase in energy efficiency and intersection flow with bi-directional vehicle-signal communication where signals adjust their timings and vehicles their speeds. Autonomous vehicles can further benefit from traffic signal information because they not only process the incoming information rather effortlessly but also can precisely control their speed and arrival time at a green light. The situation can get even better with 100%penetration of autonomous vehicles since a physical traffic light is not needed anymore. However, the optimal scheduling of the autonomous vehicle arrivals at such intersections remains an open problem. The second part of the dissertation attempts to address the scheduling problem formulation and to show its benefits in microsimulation as well as experiments.
Intellectual Merit: In the first part of this research, we study the statistical patterns hidden in the connected vehicle historical data stream in order to estimate a signal’s phase and timing (SPaT). The estimated SPaT data communicated in real-time to connected vehicles can help drivers plan over time the best vehicle velocity profile and route of travel. We use low-frequency probe data streams to show what the minimum achievable is in estimating SPaT. We use a public feed of bus location and velocity data in the city of San Francisco as an example data source. We show it is possible to estimate, fairly accurately, cycle times and duration of reds for pre-timed traffic lights traversed by buses using a few days worth of aggregated bus data. Furthermore, we also estimate the start of greens in real-time by monitoring movement of buses across intersections. The results are encouraging, given that each bus sends an update only sporadically (≈ every 200 meters) and that bus passages are infrequent (every 5-10 minutes). The accuracy of the SPaT estimations are ensured even in
presence of queues; this is achieved by extending our algorithms to include the influence of queue delay. A connected vehicle test bed is implemented in collaboration with industry. Our estimated SPaT information is communicated uni-directionally to a connected test vehicle for those traffic signals which are not connected. In the second part of the dissertation, another test bed, but with bi-directional communication capability, is implemented to transfer the connected vehicle data to an intelligent intersection controller through cellular network. We propose a novel intersection control scheme at the cyber layer to encourage platoon formation and facilitate uninterrupted intersection passage. The proposed algorithm is presented for an all autonomous vehicle environment at an intersection with no traffic lights. Our three key contributions are in communica-tion, control, and experimental evaluation: i) a scalable mechanism allowing a large number of vehicles to subscribe to the intersection controller, ii) reducing the vehicle-intersection coordination problem to a Mixed Integer Linear Program (MILP), and iii) a Vehicle-in-the-Loop (VIL) test bed with a real vehicle interacting with the intersection control cyber-layer and with our customized microsimulations in a virtual road network environment. The proposed MILP-based controller receives information such as location and speed from each subscribing vehicle and advises vehicles of the optimal time to access the intersection. The access times are computed by periodically solving a MILP with the objective of minimizing intersection delay, while ensuring intersection safety and considering each vehicle’s desired velocity. In order to estimate the fuel consumption reduction potential of the implemented system, a new method is proposed for estimating fuel consumption using the basic engine diagnostic information of the vehicle-in-the-loop car.
Broader Impacts: This research can transform not only the way we drive our vehicles at signalized intersec-tions but also the way intersections are managed. As we evaluated in a connected test vehicle in the first part of the dissertation, our SPaT estimations in conjunction with the SPaT information available directly from Traffic Management Centers, enables the drivers to plan over time the best vehicle velocity profile to reduce idling at red lights. Other fuel efficiency and safety functionalities in connected vehicles can also benefit from such information about traffic signals’ phase and timing. For example, advanced engine management strategies can shut down the engine in anticipation of a long idling interval at red, and intersection collision avoidance and active safety systems could foresee potential signal violations at signalized intersections. In addition, as shown in the second part of the dissertation, when a connected traffic signal or intersection con-troller is available, intelligent control methods can plan in real-time the best timings and the lengths of signal phases in response to prevailing traffic conditions with the use of connected vehicle data. Our MILP-based intersection control is proposed for an all autonomous driving environment; and right now, it can be utilized in smart city projects where only autonomous vehicles are allowed to travel. This is expected to transform driving experience in the sense that our linear formulations minimizes the intersection delay and number of stops significantly compared to pre-timed intersections
Effect of home-based walking on performance and quality of life in patients with heart failure
Introduction: Chronic heart failure defined as the inability of the heart to meet the demands of the tissues, which results in symptoms of fatigue or dyspnoea on energy progressing to dyspnoea at rest. The inability to perform the exercise without discomfort and poor quality of life may be one of the first symptoms experienced by patients with heart failure and is often the principal reason for seeking medical care. Objectives: The aim of the study was to find the effect of a home walking programme on the performance and quality of life in the patients with heart failure. Methods and results: Sixty patients with New York Heart Association class II and III heart failure were divided into two matched and equal groups. The quality of life scores and 6-minute walking scores were measured for each patient at entry and after 8weeks. Both groups were followed for 8weeks. The results showed between mean walking distance on the 6minutes at entry and after 8weeks in the training group (p<0.001), but no significance was seen between the control groups (p=0.351). Furthermore, results showed a significant difference between mean of quality of life scores at entry and after 8weeks in the training group, but such significance was not reported between before and after control group scores. Conclusion: The home-based walking showed improvement in the performance, exercise tolerance time and quality of life in heart failure patients. Therefore, Nurses should employ alternatives such as home exercises in the caring of heart failure patients. © 2012 Nordic College of Caring Science
Relationship between social support with anxiety, depression, and stress in pregnant women attending to health care centers in Zanjan-Iran in 2015-2016
Background: Pregnancy is associated with many emotional, physical, and social changes in women’s lives which may have an effect on the outcomes of pregnancy, so identifying moderating factors such as social support may have a preventing role on unintended outcomes of pregnancy.
Objectives: The purpose of this study was to determine the relationships between social support with anxiety, depression, and stress in pregnant women.
Methods: In this correlational study 249 pregnant women attending to health care centers in Zanjan-Iran, during 2015-2016 were selected using a multi-stage sampling method. Data was collected using three questionnaires including demographic characteristics, Wax social support (social support ftom family, friends, and others) and DASS-21 scale. The data were analyzed using descriptive and inferential statistics with SPSS software version 16.
Results: The average age of the participants were 27.57±5.56 years. The average of total perceived social support of pregnant women was 77.42±10.66, among which the most perceived social support was from the family (29.04%). Data analyses revealed weak negative and significant relationship between total social support and depression (r=-0.17) and stress (-0.13), as well as between social support from others and depression (r=-0.14) in pregnant women (P<0.05).
Conclusion: Although, in this study pregnant women received the most social support from the family, only a weak relationship was found between the total score of social support and social support by others with depression and stress. Therefore, it is recommended that more research be done on the type of social support of Azari pregnant wome
Investigation of the Relationship between Serum Leptin levels and Nausea and Vomiting of Pregnancy
Background: Worldwide, half of women suffer from nausea and vomiting in early pregnancy which generally continues to the 20th week of pregnancy. Although pathogeneses of nausea and vomiting of pregnancy as well as hyperemesis gravid arum are still unknown, some believe that nausea and vomiting of pregnancy is likely related to maternal serum leptin level.
Objectives: This study aimed to examine the relationship between leptin and pregnancy nausea and vomiting.
Methods: In this case-control study, 45 pregnant women at first and second trimesters were selected through convenient sampling. Mothers’ blood samples were taken in the 6th, 12th, 15th, and 20th weeks of pregnancy. The participants were devised into healthy, without nausea, (24) and with nausea and vomiting groups (21). The relationship among the variables was analyzed using independent t-test, Pearson correlation, regression tests, and Lambda statistic (P value <0.05).
Results: The mean age of the participants was 27.47±5.55 years, and Body Mass Index (BMI) was found to be 5.458±26.57. There was no significant difference between groups in this regard. Based on results, changes in maternal serum leptin had significant correlation with nausea and vomiting of pregnancy (p<0.04), meaning that the mean of leptin changes in patients with nausea and vomiting was significantly lower. Moreover, serum leptin at first and second trimesters of pregnancy did not have significant correlation with nausea and vomiting (p=0.5 and 0.3, respectively).
Conclusion: With regard to leptin peak level at second trimester of pregnancy, leptin changes at first and second trimesters can be a good index to predict the nausea and vomiting of pregnancy. Thus, further domestic studies are required in this respect
Churg-Strauss syndrome following cessation of allergic desensitization vaccination: a case report
<p>Abstract</p> <p>Introduction</p> <p>Churg-Strauss syndrome is a vasculitis of medium to small sized vessels. Diagnosis is mainly clinical with findings of asthma, eosinophilia, rhinosinusitis and signs of vasculitis in major organs.</p> <p>Case presentation</p> <p>We present a case of a 19-year-old Persian male who developed signs and symptoms of this syndrome related to hyposensitization treatments for allergy control.</p> <p>Conclusions</p> <p>No unifying etiology for the disease can be presented as it is found associated with environmental factors, medications, infections and is even considered a variant of asthma with predisposition to vasculitic involvement. Therefore, it is important to recognize this disease and be aware of underdiagnosis because of emphasis on pathologic evidence. Here, we present a case of allergic desensitization causing Churg-Strauss syndrome in the absence of other known factors.</p
Pyogenic spondylitis
Pyogenic spondylitis is a neurological and life threatening condition. It encompasses a broad range of clinical entities, including pyogenic spondylodiscitis, septic discitis, vertebral osteomyelitis, and epidural abscess. The incidence though low appears to be on the rise. The diagnosis is based on clinical, radiological, blood and tissue cultures and histopathological findings. Most of the cases can be treated non-operatively. Surgical treatment is required in 10–20% of patients. Anterior decompression, debridement and fusion are generally recommended and instrumentation is acceptable after good surgical debridement with postoperative antibiotic cover
Suppression of protein aggregation by chaperone modification of high molecular weight complexes
Protein misfolding and aggregation are associated with many neurodegenerative diseases, including Huntington's disease. The cellular machinery for maintaining proteostasis includes molecular chaperones that facilitate protein folding and reduce proteotoxicity. Increasing the protein folding capacity of cells through manipulation of DNAJ chaperones has been shown to suppress aggregation and ameliorate polyglutamine toxicity in cells and flies. However, to date these promising findings have not been translated to mammalian models of disease. To address this issue, we developed transgenic mice that over-express the neuronal chaperone HSJ1a (DNAJB2a) and crossed them with the R6/2 mouse model of Huntington's disease. Over-expression of HSJ1a significantly reduced mutant huntingtin aggregation and enhanced solubility. Surprisingly, this was mediated through specific association with K63 ubiquitylated, detergent insoluble, higher order mutant huntingtin assemblies that decreased their ability to nucleate further aggregation. This was dependent on HSJ1a client binding ability, ubiquitin interaction and functional co-operation with HSP70. Importantly, these changes in mutant huntingtin solubility and aggregation led to improved neurological performance in R6/2 mice. These data reveal that prevention of further aggregation of detergent insoluble mutant huntingtin is an additional level of quality control for late stage chaperone-mediated neuroprotection. Furthermore, our findings represent an important proof of principle that DNAJ manipulation is a valid therapeutic approach for intervention in Huntington's disease
Effect of nutrients on total lipid content and fatty acids profile of Scenedesmus obliquus
- …