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Open Access Publications from the University of California

Scholarly Works (19 results)

  • Article
Working Papers (2002)

This paper introduces an adaptive signal control system utilizing an on-line signal performance measure. Unlike conventional signal control systems, the proposed method employs real-time delay estimation and an on-line signal timing update algorithm. As a signal performance measure, intersection delay for each phase is measured in real-time via an advanced surveillance system that re-identifies individual vehicles both at upstream and downstream stations using vehicle waveforms obtained from advanced inductive loop detectors. In each cycle, the signal timing plan is optimized based on the delay estimated from the vehicle re- identification technology. The main thrust of the algorithm is the on-line control capability utilizing direct intersection delay measures. A description of the overall control system architecture and the optimization algorithm is addressed in this paper. Performance of the proposed system is evaluated with a high-performance microscopic traffic simulation program, Paramics, and the preliminary results have proven the promising properties of the proposed system. Key Words: adaptive signal control; vehicle re-identification; intersection delay estimation; signal plan optimization

    Cover page: Adaptive Signal Control System with On-line Performance Measure for Single Intersection
    • Article
    Working Papers (1999)

    This project will further adapt and enhance the previous research of relevance to event-based Advanced Traveler Information Systems (ATIS) and implement the algorithms for traffic management in Anaheim. The implementation involves the Caltrans-UCI ATMS research testbed framework at the UCI Institute of Transportation Studies, as well as the physical hardware available for communication to the city of Anaheim. The analytical algorithms proposed for use here include those for static and dynamic traffic assignment. and the modeling schemes used are the result of previous PATH and Testbed research projects on traffic simulation and driver behavioral response to information. The essential part of algorithmic research will be to adapt the network optimization algorithms to generate traffic rerouting plans, which involve aggregation of network paths and their translation to a format usable for changeable message signs existing in Anaheim. as well as other event-based information supply hardware. The implementation plan envisages a framework that is usable by the city for event-based congestion management, but its useis left to the city's decision. Key words: Advanced Traveler Information Systems, Optimal Routing, Dynamic Traffic Assignment, Changeable Message Signs

      Cover page: Event-based ATIS: Practical Implementation and Evaluation of Optimized Strategies (Part I)
      • Article
      Research Reports (2001)
      This project further adapt and enhance the previous research of relevance to event-based Advanced Traveler Information Systems (ATIS) and implement the algorithms for traffic management in Anaheim. This study is also answering some basic questions in ATIS implementation associated with routing strategies, driver’s compliance and network performance. This research develops algorithms for static and dynamic optimal Changeable Message Signs (CMS). The optimized CMS schemes are based on performance evaluations using a traffic simulation-based evaluation model, DYNASMART (Dynamic Network Assignment Simulation Model for Advanced Road Telematics). Performance of ATIS depends on drivers’ compliance behavior, and the compliance issue is addressed in this research. This study develops a framework of driver’s compliance model, and incorporates it into the evaluation framework. The model includes inherent value of guidance system, and the value is analyzed via day-to-day update approach. A limited field test is implemented for the event traffic management. The implementation involves the Caltrans-UCI ATMS research testbed framework at the UCI Institute of Transportation Studies, as well as the physical hardware available for communication to the city of Anaheim. The analytical and heuristic algorithms proposed for use here include those for static and dynamic traffic simulation-assignment. The essential part of algorithmic research is to adapt the network optimization algorithms to generate traffic rerouting plans, which involve aggregation of network paths and their translation to a format usable for changeable message signs existing in Anaheim, as well as other event-based information supply hardware.
        Cover page: Event-based ATIS: Practical Implementation and Evaluation of Optimized Strategies
        • Article
        • Peer Reviewed
        UCLA Previously Published Works (2017)
        Glutamate is the major excitatory neurotransmitter in the central nervous system, and related signaling involves both AMPA and NMDA subtype receptors. The expression of glutamate receptors is dynamically regulated during development. Recent studies showed that the dysregulation of glutamate receptor expression and function is associated with neurodevelopmental disorders including intellectual disability. Previously, a Noonan syndrome (NS)-associated SHP2 mutation (SHP2D61G) was shown to increase the synaptic delivery of AMPA receptor, subsequently impairing synaptic plasticity and learning in adult mice. However, how the mutant SHP2 affects glutamate receptor expression during development is not known. Here, we found that the SHP2D61G differentially regulates the expression of AMPA and NMDA receptors depending on the stage of neuronal maturation. In cultured neurons (immature stage; DIV 6), overexpression of SHP2D61G significantly increased the average size and the number of NMDA receptor-containing particles, but not those with AMPA receptors. In early matured neurons (DIV 12), SHP2D61G significantly increased only the average size of AMPA receptor particles, and subsequently increased their number in matured neurons (DIV 18). Importantly, all the changes described above for SHP2D61G neurons were reversed by inhibiting MAPK. These data demonstrate that the increased activation of MAPK signaling pathway by SHP2D61G could deregulate the surface expression of synaptic receptors during neuronal development, which likely contributes to cognitive impairments in NS patients.
          Cover page: Noonan syndrome-associated SHP2 mutation differentially modulates the expression of postsynaptic receptors according to developmental maturation
          • Article
          Working Papers (2001)

          This paper presents an on-line signal control scheme integrated with the real-time intersection delay estimation technology. The primary goal of this study is to design a complementary optimization module to the existing controller to minimize the total delay experienced by traffic and improve the system performance at the signalized intersections. This paper proposes a feedback control algorithm that optimizes the signal timing plan based on delay estimated via vehicle re-identification technology. Main thrust of the algorithm is on-line control capability utilizing direct delay measures. A description of overall signal control system architecture and optimization algorithm is given in this paper. Extensive simulation experiments are preformed with a high-performance microscopic traffic simulation program, Paramics, and the preliminary results have proved the promising properties of our proposed system.

            Cover page: On-line Traffic Signal Control Scheme with Real-time Delay Estimation Technology
            • Article
            • Peer Reviewed
            UC San Francisco Previously Published Works (2022)
            Low-grade gliomas (LGGs), which harbor an isocitrate dehydrogenase (IDH) mutation, have a better prognosis than their high-grade counterparts; nonetheless, they remain incurable and impart significant negative impacts on patients' quality of life. Although immunotherapies represent a novel avenue of treatment for patients with LGGs, they have not yet been successful. Accurately selecting and evaluating immunotherapies requires a detailed understanding of LGG tumor immunology and the underlying tumor immune phenotype. A growing body of literature suggests that LGGs significantly differ in their immunology from high-grade gliomas, highlighting the importance of investigation into LGG immunology specifically. In this review, the authors aimed to discuss relevant research surrounding the LGG tumor immune microenvironment, including immune cell infiltration, tumor immunogenicity, checkpoint molecule expression, the impact of an IDH mutation, and implications for immunotherapies, while also briefly touching on current immunotherapy trials and future directions for LGG immunology research.
              Cover page: The immunology of low-grade gliomas.
              • Article
              • Peer Reviewed
              UC San Francisco Previously Published Works (2022)
              Pituitary adenomas (PAs) have been shown to cause excess cardiovascular disease comorbidity and mortality. Cerebrovascular disease (CeVD) is a small subset of cardiovascular disease with high morbidity, and its risk in patients with pituitary adenomas has been sparingly explored. In this review, we examine what is known about the prevalence of cerebrovascular disease in patients with PAs, from its initial discovery in 1970 to present. An abundance of literature describes increased cerebrovascular mortality in patients with acromegaly, while research on other PA subtypes is less frequent but shows a similarly elevated CeVD mortality relative to healthy populations. We also review how cerebrovascular risk changes after PAs are treated, with PA treatment appearing to prevent further accumulation of cerebrovascular risk without reversing prior elevations. While acromegaly-associated CeVD appears to be caused by elevated growth hormone (GH) levels and Cushing disease's elevated glucocorticoids similarly cause durable alterations in cerebrovascular structure and function, less is known about the mechanisms behind CeVD in other PA subpopulations. Proposed pathophysiologies include growth hormone deficiency inducing vessel wall damage or other hormone deficits causing increased atherosclerotic disease. Early diagnosis and treatment of PAs may be the key to minimizing lifetime CeVD risk elevations. More research is needed to better understand the mechanisms behind the increased CeVD seen in patients with PAs. Physicians caring for PA patients must remain vigilant for signs and symptoms of cerebrovascular disease in this patient population.
                Cover page: Pituitary adenomas and cerebrovascular disease: A review on pathophysiology, prevalence, and treatment
                • Article
                • Peer Reviewed
                UC San Francisco Previously Published Works (2019)
                Sleep and wakefulness control in the mammalian brain requires the coordination of various discrete interconnected neurons. According to the most conventional sleep model, wake-promoting neurons (WPNs) and sleep-promoting neurons (SPNs) compete for network dominance, creating a systematic "switch" that results in either the sleep or awake state. WPNs and SPNs are ubiquitous in the brainstem and diencephalon, areas that together contain <1% of the neurons in the human brain. Interestingly, many of these WPNs and SPNs co-express and co-release various types of the neurotransmitters that often have opposing modulatory effects on the network. Co-transmission is often beneficial to structures with limited numbers of neurons because it provides increasing computational capability and flexibility. Moreover, co-transmission allows subcortical structures to bi-directionally control postsynaptic neurons, thus helping to orchestrate several complex physiological functions such as sleep. Here, we present an in-depth review of co-transmission in hypothalamic WPNs and SPNs and discuss its functional significance in the sleep-wake network.
                  • Article
                  Research Reports (2005)

                  Travel time variability is increasingly being recognized as a major factor influencing travel decisions and, consequently, as an important performance measure in transportation management. In this research project, we examine a number of questions related to travel time variability: How should travel time variability be quantified at both the section level as well as at the route level?; How do travelers value travel time and its reliability?; How much does the travel time reliability contribute to travelers' route choices?; How much variation is there in travelers' preferences regarding the potential tradeoff between reliability and travel time itself?; How can travel time variability be incorporated into the route choice models for transportation planning purposes?; and, How can the effects of travel time reliability be incorporated in considering risk-taking behavior in route choice models? Answering these questions can help in the design and evaluation of transportation planning and managing strategies.

                    Cover page: Considering Risk-Taking Behavior in Travel Time Reliability
                    • Article
                    • Peer Reviewed
                    UC Riverside Previously Published Works (2021)
                    Herein, we describe interfacially-assembled [7]helicene films that were deposited on graphene monolayer using the Langmuir-Schaefer deposition by utilizing the interactions of nonplanar (helicene) and planar (graphene) π-π interactions as functional antifouling coatings. Bacterial adhesion of Staphylococcus aureus on helicene-graphene films was noticeably lower than that on bare graphene, up to 96.8% reductions in bacterial adhesion. The promising bacterial antifouling characteristics of helicene films was attributed to the unique molecular geometry of helicene, i.e., nano-helix, which can hinder the nanoscale bacterial docking processes on a surface. We envision that helicene-graphene films may eventually be used as protective coatings against bacterial antifouling on the electronic components of clinical and biomedical devices.
                      Cover page: Bacterial Antifouling Characteristics of Helicene-Graphene Films.
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