Optimal efficiency control of PM hybrid motor drives for electrical vehicles

The paper deals with the control of a novel brushless PM hybrid motor to optimize its efficiency. The approach is to adaptively adjust the field current to minimize the total loss based on its potential for a high efficiency over a wide torque-speed region. The optimal controller has good performance for electrical vehicles.published_or_final_versio

An automotive thermoelectric-photovoltaic hybrid energy system

In recent years, there has been active research on exhaust gas waste heat energy recovery for automobiles. Meanwhile, the use of solar energy is also proposed to promote on-board renewable energy and hence to improve their fuel economy. In this paper, a new thermoelectric-photovoltaic hybrid energy system is proposed and implemented for automobiles. The key is to newly develop the power conditioning circuit using maximum power point tracking so that the output power of the proposed hybrid energy system can be maximized. An experimental system is prototyped and tested to verify the validity of the proposed system. © Copyright 2011 IEEE - All Rights Reserved.published_or_final_versionThe 2010 IEEE Vehicle Power and Propulsion Conference (VPPC), Lille, France, 1-3 September 2010. In Proceedings of VPPC, 2010, p. 1-

Constructing power system restoration strategies

System restoration is an integral part of the overall defense system against catastrophic outages. The nature of system restoration problem involves status assessment, optimization of generation capability and load pickup. The optimization problem needs to take into numerous practical considerations and, therefore, it cannot be formulated as one single optimization problem. The other critical consideration for the development of decision support tools is its generality, i.e., the tools should be portable from a system to another with minimal customization. This presentation will provide a comprehensive methodology for construction of system restoration strategies. The strategy adopted by each power system differs, depending on the system characteristics and policies. A new method based on the concept of "generic restoration milestones" and "generic restoration actions" has been developed. A specific restoration strategy can be synthesized by a combination of the milestones and actions based on the actual system conditions. The decision support tool is expected to reduce the restoration time, thereby improving the system reliability.published_or_final_versionThe 6th International Conference on Electrical and Electroincs Engineering (ELECO 2009), Bursa, Turkey, 5-8 November 2009. In Proceedings of the International Conference on Electrical and Electronics Engineering, 2009, p. I8-I1

Impaired vowel discrimination in Mandarin-speaking congenital amusics

2015-2016 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe

Conformative Filtering for Implicit Feedback Data

Implicit feedback is the simplest form of user feedback that can be used for item recommendation. It is easy to collect and is domain independent. However, there is a lack of negative examples. Previous work tackles this problem by assuming that users are not interested or not as much interested in the unconsumed items. Those assumptions are often severely violated since non-consumption can be due to factors like unawareness or lack of resources. Therefore, non-consumption by a user does not always mean disinterest or irrelevance. In this paper, we propose a novel method called Conformative Filtering (CoF) to address the issue. The motivating observation is that if there is a large group of users who share the same taste and none of them have consumed an item before, then it is likely that the item is not of interest to the group. We perform multidimensional clustering on implicit feedback data using hierarchical latent tree analysis (HLTA) to identify user `tastes' groups and make recommendations for a user based on her memberships in the groups and on the past behavior of the groups. Experiments on two real-world datasets from different domains show that CoF has superior performance compared to several common baselines

Components of the Hematopoietic Compartments in Tumor Stroma and Tumor-Bearing Mice

Solid tumors are composed of cancerous cells and non-cancerous stroma. A better understanding of the tumor stroma could lead to new therapeutic applications. However, the exact compositions and functions of the tumor stroma are still largely unknown. Here, using a Lewis lung carcinoma implantation mouse model, we examined the hematopoietic compartments in tumor stroma and tumor-bearing mice. Different lineages of differentiated hematopoietic cells existed in tumor stroma with the percentage of myeloid cells increasing and the percentage of lymphoid and erythroid cells decreasing over time. Using bone marrow reconstitution analysis, we showed that the tumor stroma also contained functional hematopoietic stem cells. All hematopoietic cells in the tumor stroma originated from bone marrow. In the bone marrow and peripheral blood of tumor-bearing mice, myeloid populations increased and lymphoid and erythroid populations decreased and numbers of hematopoietic stem cells markedly increased with time. To investigate the function of hematopoietic cells in tumor stroma, we co-implanted various types of hematopoietic cells with cancer cells. We found that total hematopoietic cells in the tumor stroma promoted tumor development. Furthermore, the growth of the primary implanted Lewis lung carcinomas and their metastasis were significantly decreased in mice reconstituted with IGF type I receptor-deficient hematopoietic stem cells, indicating that IGF signaling in the hematopoietic tumor stroma supports tumor outgrowth. These results reveal that hematopoietic cells in the tumor stroma regulate tumor development and that tumor progression significantly alters the host hematopoietic compartment

Temperature dependent distinct coupling and dispersions of heavy- and light-hole excitonic polaritons in ZnO

Distinct coupling behavior of heavy- and light-hole excitonic polaritons in ZnO was unveiled by investigating the optical reflectance spectra of a high quality ZnO single crystal as a function of temperature both experimentally and theoretically. A resonance like coupling region was found at a temperature of around 50 K at which several relevant physical quantities such as the transverse exciton transition energy, polarizability, and damping parameters of the two kinds of excitonic polaritons were revealed to overturn. Calculated dispersions correctly reflect the nature of coupled photon and exciton and reproduce the spectral structures of the interacting polaritons. © 2012 American Institute of Physics.published_or_final_versio

Novel permanent magnet motor drives for electric vehicles

Novel permanent magnet (PM) motor drives have been successfully developed to fulfil the special requirements for electric vehicles such as high power density, high efficiency, high starting torque, and high cruising speed. These PM motors are all brushless and consist of various types, namely rectangular-fed, sinusoidal-fed, surface-magnet, buried-magnet, and hybrid. The advent of novel motor configurations lies on the unique electro-magnetic topology, including the concept of multipole magnetic circuit and full slot-pitch coil span arrangements, leading to a reduction in both magnetic yoke and copper, decoupling of each phase flux path, and hence an increase in both power density and efficiency. Moreover, with the use of fractional number of slots per pole per phase, the cogging torque can be eliminated. On the other hand, by employing the claw-type rotor structure and fixing an additional field winding as the inner stator, these PM hybrid motors can further provide excellent controllability and improve efficiency map. In the PM motors, by purposely making use of the transformer EMF to prevent the current regulator from saturation, a novel control approach is developed to allow for attaining high-speed constant-power operation which is particularly essential for electric vehicles during cruising. Their design philosophy, control strategy, theoretical analysis, computer simulation, experimental tests and application to electric vehicles are described. © 1996 IEEE.published_or_final_versio

Patients' satisfaction and prevalence of complications on surgical extraction of third molar.

OBJECTIVES: To study patients' satisfaction and prevalence of complications in surgical extraction of impacted third molar by senior dentists and recently graduated dentists in a university dental clinic. METHOD: Patients who had impacted third molar extraction in a university dental clinic by two associate dentists who had 15 years of experience were evaluated in this study. Patients' age, sex, history of pericoronitis, tooth extracted, and radiographic assessment of the impacted tooth were recorded. Immediately after suture removal, the patients were invited to indicate their satisfaction on a Likert scale of 1-5. RESULTS: A total of 546 patients received extraction, and 251 patients were operated by associate dentists. Patient satisfaction was higher among those who had noncomplicated surgery (P=0.007), short treatment time (P<0.001), and had no postsurgical emergency appointments (P<0.001). The prevalence of seeking postsurgical emergency appointments was 9.2%. The reasons were severe pain (4.8%), swelling (2.6%), bleeding (2.4%), alveolar osteitis (0.9%), paresthesia (0.9), and trismus (0.5%). The prevalence of postsurgical complication(s) in associate dentists and senior dentists was 11.6% and 7.1%, respectively (P=0.050). The mean satisfaction scores for associate dentists and senior dentists were 4.17 and 3.95, respectively (P=0.002). CONCLUSION: Although a higher rate of postsurgical complications was observed among the patients treated by the recently graduated dentists, their patients' satisfaction scores were higher than that of the senior dentists. Around 9% of patients attended postsurgical emergency appointments, and their common reason was severe pain.published_or_final_versio