Showing papers by "University of California, Irvine published in 1998"
University of Tokyo1, Boston University2, Brookhaven National Laboratory3, University of California, Irvine4, California State University5, George Mason University6, Gifu University7, University of Hawaii at Manoa8, Kobe University9, Los Alamos National Laboratory10, Louisiana State University11, University of Maryland, College Park12, University of Chicago13, Stony Brook University14, Niigata University15, Osaka University16, Seoul National University17, Tohoku University18, Tokai University19, Tokyo Institute of Technology20, University of Warsaw21, University of Washington22, Stanford University23
Abstract: We present an analysis of atmospheric neutrino data from a 33.0 kton yr (535-day) exposure of the Super-Kamiokande detector. The data exhibit a zenith angle dependent deficit of muon neutrinos which is inconsistent with expectations based on calculations of the atmospheric neutrino flux. Experimental biases and uncertainties in the prediction of neutrino fluxes and cross sections are unable to explain our observation. The data are consistent, however, with two-flavor ${\ensuremath{
u}}_{\ensuremath{\mu}}\ensuremath{\leftrightarrow}{\ensuremath{
u}}_{\ensuremath{\tau}}$ oscillations with ${sin}^{2}2\ensuremath{\theta}g0.82$ and $5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}l\ensuremath{\Delta}{m}^{2}l6\ifmmode\times\else\texttimes\fi{}1{0}^{\ensuremath{-}3}\mathrm{eV}{}^{2}$ at 90% confidence level.
3,784 citations
Posted Content•
TL;DR: This paper proposed a theory of securities market under- and overreactions based on two well-known psychological biases: investor overconfidence about the precision of private information; and biased self-attribution, which causes asymmetric shifts in investors' confidence as a function of their investment outcomes.
Abstract: We propose a theory of securities market under- and overreactions based on two well-known psychological biases: investor overconfidence about the precision of private information; and biased self-attribution, which causes asymmetric shifts in investors' confidence as a function of their investment outcomes. We show that overconfidence implies negative long-lag autocorrelations, excess volatility, and, when managerial actions are correlated with stock mispricing, public-event-based return predictability. Biased self-attribution adds positive short-lag autocorrelations (momentum), short-run earnings drift, but negative correlation between future returns and long-term past stock market and accounting performance. The theory also offers several untested implications and implications for corporate financial policy.
Prepublication version available at https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2017
3,303 citations
TL;DR: Human-subject studies confirm the prediction of animal work that the amygdala is involved with the formation of enhanced declarative memory for emotionally arousing events and suggest that the amygdaloid complex serves to influence memory-storage processes in other brain regions.
1,505 citations
Proceedings Article•
24 Jul 1998TL;DR: This work proposes a representation for collaborative filtering tasks that allows the application of virtually any machine learning algorithm, and identifies the shortcomings of current collaborative filtering techniques and proposes the use of learning algorithms paired with feature extraction techniques that specifically address the limitations of previous approaches.
Abstract: Predicting items a user would like on the basis of other users’ ratings for these items has become a well-established strategy adopted by many recommendation services on the Internet. Although this can be seen as a classification problem, algorithms proposed thus far do not draw on results from the machine learning literature. We propose a representation for collaborative filtering tasks that allows the application of virtually any machine learning algorithm. We identify the shortcomings of current collaborative filtering techniques and propose the use of learning algorithms paired with feature extraction techniques that specifically address the limitations of previous approaches. Our best-performing algorithm is based on the singular value decomposition of an initial matrix of user ratings, exploiting latent structure that essentially eliminates the need for users to rate common items in order to become predictors for one another's preferences. We evaluate the proposed algorithm on a large database of user ratings for motion pictures and find that our approach significantly outperforms current collaborative filtering algorithms.
1,169 citations
TL;DR: It is shown that rats have impaired performance in a water-maze spatial task after being given footshock 30 min before retention testing but are not impaired when footshock is given 2’min or 4 h before testing, which suggests that the retention impairment is directly related to increased adrenocortical function.
Abstract: Extensive evidence from animal and human studies indicates that stress and glucocorticoids influence cognitive function. Previous studies have focused exclusively on glucocorticoid effects on acquisition and long-term storage of newly acquired information. Here we report that stress and glucocorticoids also affect memory retrieval. We show that rats have impaired performance in a water-maze spatial task after being given footshock 30 min before retention testing but are not impaired when footshock is given 2 min or 4 h before testing. These time-dependent effects on retention performance correspond to the circulating corticosterone levels at the time of testing, which suggests that the retention impairment is directly related to increased adrenocortical function. In support of this idea, we find that suppression of corticosterone synthesis with metyrapone blocks the stress-induced retention impairment. In addition, systemic corticosterone administered to non-stressed rats 30 min before retention testing induces dose-dependent retention impairment. The impairing effects of stress and glucocorticoids on retention are not due to disruption of spatial navigation per se. Our results indicate that besides the well described effects of stress and glucocorticoids on acquisition and consolidation processes, glucocorticoids also affect memory retrieval mechanisms.
1,148 citations
Book•
01 Jan 1998TL;DR: This book is aimed both at biologists and biochemists who need to understand new data-driven algorithms and at those with a primary background in physics, mathematics, statistics, or computer science who needs to know more about applications in molecular biology.
Abstract: In this book Pierre Baldi and Soren Brunak present the key machine learning approaches and apply them to the computational problems encountered in the analysis of biological data. The book is aimed both at biologists and biochemists who need to understand new data-driven algorithms and at those with a primary background in physics, mathematics, statistics, or computer science who need to know more about applications in molecular biology.
939 citations
TL;DR: The structure of the adh1 region appears to be standard relative to the other gene-containing regions of the maize genome, thus suggesting that retrotransposon insertions have increased the size of the corn genome from approximately 1200 Mb to 2400 Mb in the last three million years.
Abstract: Retrotransposons, transposable elements related to animal retroviruses, are found in all eukaryotes investigated and make up the majority of many plant genomes Their ubiquity points to their importance, especially in their contribution to the large-scale structure of complex genomes The nature and frequency of retro-element appearance, activation and amplification are poorly understood in all higher eukaryotes Here we employ a novel approach to determine the insertion dates for 17 of 23 retrotransposons found near the maize adh1 gene, and two others from unlinked sites in the maize genome, by comparison of long terminal repeat (LTR) divergences with the sequence divergence between adh1 in maize and sorghum All retrotransposons examined have inserted within the last six million years, most in the last three million years The structure of the adh1 region appears to be standard relative to the other gene-containing regions of the maize genome, thus suggesting that retrotransposon insertions have increased the size of the maize genome from approximately 1200 Mb to 2400 Mb in the last three million years Furthermore, the results indicate an increased mutation rate in retrotransposons compared with genes
937 citations
TL;DR: This article presented a problem-centered organizing framework of trust, in which prominent conceptualizations of trust and distrust from the organizational and allied social sciences are categorized based on the questions they attempt to answer.
Abstract: We present a problem-centered organizing framework of trust, in which prominent conceptualizations of trust and distrust from the organizational and allied social sciences are categorized based on the questions they attempt to answer. The framework we outline here is intended to complement earlier typologies by suggesting alternative strategies for employing the diverse trust literature, identifying questions that could be profitably addressed through interdisciplinary research efforts, and distinguishing disagreements where debate and research would seem to be especially worthwhile from those where such activities would appear to be much less useful.
814 citations
TL;DR: The authors describe and apply choice models, including generalizations of logit called mixed logits, that do not exhibit the restrictive "independence from irrelevant alternatives" property and can approximate any substitution pattern.
739 citations
TL;DR: In this paper, a model of active interpersonal information search that is tested by using a method in which information seeker and source perceptions were obtained was used to study the phenomenon of interpersonal word-of-mouth communication.
Abstract: Although interpersonal word-of-mouth communication, by definition, takes place between two people, rarely has the phenomenon of word of mouth been studied using both members of the dyad. Building on the literature, this article offers a model of active interpersonal information search that is tested by using a method in which information seeker and source perceptions were obtained. Source characteristics were important determinants of interpersonal influence, but seeker characteristics also played an important role. Interestingly, it proved useful to distinguish between demographic and attitudinal homophily of seeker and source as the former was inversely and the latter directly related to interpersonal influence.
718 citations
Proceedings Article•
27 Aug 1998TL;DR: In this article, the problem of finding rules relating patterns in a time series to other patterns in that series, or patterns in one series to patterns in another series, was considered, and adaptive methods for finding rules of the above type from time-series data were described.
Abstract: We consider the problem of finding rules relating patterns in a time series to other patterns in that series, or patterns in one series to patterns in another series A simple example is a rule such as "a period of low telephone call activity is usually followed by a sharp rise in call volume" Examples of rules relating two or more time series are "if the Microsoft stock price goes up and Intel falls, then IBM goes up the next day," and "if Microsoft goes up strongly for one day, then declines strongly on the next day, and on the same days Intel stays about level, then IBM stays about level" Our emphasis is in the discovery of local patterns in multivariate time series, in contrast to traditional time series analysis which largely focuses on global models Thus, we search for rules whose conditions refer to patterns in time series However, we do not want to define beforehand which patterns are to be used; rather, we want the patterns to be formed from the data in the context of rule discovery We describe adaptive methods for finding rules of the above type from time-series data The methods are based on discretizing the sequence by methods resembling vector quantization We first form subsequences by sliding a window through the time series, and then cluster these subsequences by using a suitable measure of time-series similarity The discretized version of the time series is obtained by taking the cluster identifiers corresponding to the subsequence Once the time-series is discretized, we use simple rule finding methods to obtain rules from the sequence We present empirical results on the behavior of the method
01 Apr 1998
TL;DR: An architecture-based approach to runtime software evolution is presented and the role of software connectors in supporting runtime change is highlighted and an initial implementation of a tool suite for supporting the runtime modification of software architectures is presented.
Abstract: Continuous availability is a critical requirement for an important class of software systems. For these systems, runtime system evolution can mitigate the costs and risks associated with shutting down and restarting the system for an update. We present an architecture-based approach to runtime software evolution and highlight the role of software connectors in supporting runtime change. An initial implementation of a tool suite for supporting the runtime modification of software architectures, called ArchStudio, is presented.
University of Tokyo1, Boston University2, Seoul National University3, Brookhaven National Laboratory4, University of California, Irvine5, California State University6, George Mason University7, Gifu University8, University of Hawaii at Manoa9, Kobe University10, Los Alamos National Laboratory11, Louisiana State University12, University of Maryland, College Park13, University of Chicago14, Miyagi University of Education15, Stony Brook University16, Niigata University17, Shizuoka University18, Osaka University19, Tohoku University20, Tokai University21, Tokyo Institute of Technology22, University of Warsaw23, University of Washington24
TL;DR: The first results of the solar neutrino flux measurement from Super-Kamiokande are presented in this article, where the results are obtained from data taken between 31 May 1996, and 23 June 1997.
Abstract: The first results of the solar neutrino flux measurement from Super-Kamiokande are presented. The results shown here are obtained from data taken between 31 May 1996, and 23 June 1997. Using our measurement of recoil electrons with energies above 6.5 MeV, we infer the total flux of ${}^{8}\mathrm{B}$ solar neutrinos to be $2.42\ifmmode\pm\else\textpm\fi{}0.06(\mathrm{stat}{)}_{\ensuremath{-}0.07}^{+0.10}(\mathrm{syst})\ifmmode\times\else\texttimes\fi{}{10}^{6}\mathrm{cm}{}^{\ensuremath{-}2}{\mathrm{s}}^{\ensuremath{-}1}$. This result is consistent with the Kamiokande measurement and is 36% of the flux predicted by the BP95 solar model. The flux is also measured in 1.5 month subsets and shown to be consistent with a constant rate.
Saint Louis University1, Emory University2, University of Pittsburgh3, George Washington University Hospital4, Food and Drug Administration5, Stanford University6, Mayo Clinic7, University of Cincinnati Academic Health Center8, University of California, Irvine9, University of California, Los Angeles10, Pennsylvania State University11
TL;DR: The document emphasizes the importance of rhinitis management for comorbid conditions (asthma, sinusitis, otitis media) and when consultation with an allergist-immunologist should be considered.
Abstract: This document contains complete guidelines for diagnosis and management of rhinitis developed by the Joint Task Force on Practice Parameters in Allergy, Asthma and Immunology, representing the American Academy of Allergy, Asthma and Immunology, the American College of Allergy, Asthma and Immunology and the Joint Council on Allergy, Asthma and Immunology. The guidelines are comprehensive and begin with statements on clinical characteristics and diagnosis of different forms of rhinitis (allergic, non-allergic, occupational rhinitis, hormonal rhinitis [pregnancy and hypothyroidism], drug-induced rhinitis, rhinitis from food ingestion), and other conditions that may be confused with rhinitis. Recommendations on patient evaluation discuss appropriate use of history, physical examination, and diagnostic testing, as well as unproven or inappropriate techniques that should not be used. Parameters on management include use of environmental control measures, pharmacologic therapy including recently introduced therapies and allergen immunotherapy. Because of the risks to patients and society from sedation and performance impairment caused by first generation antihistamines, second generation antihistamines that reduce or eliminate these side effects should usually be considered before first generation antihistamines for the treatment of allergic rhi-nitis. The document emphasizes the importance of rhinitis management for co-morbid conditions (asthma, sinusitis, otitis media). Guidelines are also presented on special considerations in patients subsets (children, the elderly, pregnancy, athletes and patients with rhinitis medicamentosa); and when consultation with an allergist-immunologist should be considered.
TL;DR: The unexpected recognition of the substrate, L-arginine, at the H4B site indicates that this site is poised to stabilize a positively charged pterin ring and suggests a model involving a cationic pterIn radical in the catalytic cycle.
TL;DR: In this article, night-time observations of molecular chlorine concentrations at a North American coastal site during onshore wind flow conditions that cannot be explained using known chlorine chemistry were reported, and the measured Cl2 mixing ratios range from <10 to 150 parts per 1012 (ppt), exceeding those predicted for marine air by more than an order of magnitude.
Abstract: The fate of many atmospheric trace species, including pollutants such as nitrogen oxides and some volatile organic compounds, is controlled by oxidation reactions In the daytime troposphere, these reactions are dominated by photochemically produced OH radicals; at night and in polluted environments, NO3 radicals are an important oxidant1 Ozone can contribute to the oxidation of atmospheric species during both day and night1 In recent years, laboratory investigations2,3,4, modelling studies5,6,7, measured Cl deficits in marine aerosols8 and species-nonspecific observations9,10,11 of gaseous inorganic chlorine compounds other than HCl have suggested that reactive halogen species may contribute significantly to—or even locally dominate—the oxidative capacity of the lower marine troposphere Here we report night-time observations of molecular chlorine concentrations at a North American coastal site during onshore wind flow conditions that cannot be explained using known chlorine chemistry The measured Cl2 mixing ratios range from <10 to 150 parts per 1012 (ppt), exceeding those predicted5 for marine air by more than an order of magnitude Using the observed chlorine concentrations and a simple photochemical box model, we estimate that a hitherto unrecognized chlorine source must exist that produces up to 330 ppt Cl2 per day The model also indicates that early-morning photolysis of molecular chlorine can yield sufficiently high concentrations of chlorine atoms to render the oxidation of common gaseous compounds by this species 100 times faster than the analogous oxidation reactions involving the OH radical, thus emphasizing the locally significant effect of chlorine atoms on the concentrations and lifetimes of atmospheric trace species in both the remote marine boundary layer and coastal urban areas
Proceedings Article•
27 Aug 1998TL;DR: An extended representation of time series that allows fast, accurate classification and clustering in addition to the ability to explore time series data in a relevance feedback framework is introduced.
Abstract: We introduce an extended representation of time series that allows fast, accurate classification and clustering in addition to the ability to explore time series data in a relevance feedback framework. The representation consists of piece-wise linear segments to represent shape and a weight vector that contains the relative importance of each individual linear segment. In the classification context, the weights are learned automatically as part of the training cycle. In the relevance feedback context, the weights are determined by an interactive and iterative process in which users rate various choices presented to them. Our representation allows a user to define a variety of similarity measures that can be tailored to specific domains. We demonstrate our approach on space telemetry, medical and synthetic data.
TL;DR: X-ray diffraction of bacteriorhodopsin crystals grown in cubic lipid phase revealed unexpected two-fold symmetries that indicate merohedral twinning along the crystallographic c axis.
Abstract: Photoisomerization of the retinal of bacteriorhodopsin initiates a cyclic reaction in which a proton is translocated across the membrane. Studies of this protein promise a better understanding of how ion pumps function. Together with a large amount of spectroscopic and mutational data, the atomic structure of bacteriorhodopsin, determined in the last decade at increasing resolutions, has suggested plausible but often contradictory mechanisms. X-ray diffraction of bacteriorhodopsin crystals grown in cubic lipid phase revealed unexpected two-fold symmetries that indicate merohedral twinning along the crystallographic c axis. The structure, refined to 2.3 angstroms taking this twinning into account, is different from earlier models, including that most recently reported. One of the carboxyl oxygen atoms of the proton acceptor Asp85 is connected to the proton donor, the retinal Schiff base, through a hydrogen-bonded water and forms a second hydrogen bond with another water. The other carboxyl oxygen atom of Asp85 accepts a hydrogen bond from Thr89. This structure forms the active site. The nearby Arg82 is the center of a network of numerous hydrogen-bonded residues and an ordered water molecule. This network defines the pathway of the proton from the buried Schiff base to the extracellular surface.
TL;DR: System administrative changes have been made to improve security and efficiency, and to make MITOMAP compatible with a new automatic mtDNA sequence analyzer known as Mitomaster.
Abstract: MITOMAP (http://www.MITOMAP.org), a database for the human mitochondrial genome, has grown rapidly in data content over the past several years as interest in the role of mitochondrial DNA (mtDNA) variation in human origins, forensics, degenerative diseases, cancer and aging has increased dramatically. To accommodate this information explosion, MITOMAP has implemented a new relational database and an improved search engine, and all programs have been rewritten. System administrative changes have been made to improve security and efficiency, and to make MITOMAP compatible with a new automatic mtDNA sequence analyzer known as Mitomaster.
TL;DR: This work develops a general framework for thinking about the thermodynamics of membrane protein stability that centers on interfacial interactions and describes an experimentally determined whole-residue interfacial hydrophobicity scale that reveals the central role of the peptide bond in partitioning and folding.
TL;DR: In this article, a long-baseline reactor-neutrino vacuum-oscillation experiment (CHOOZ 1 ) was presented, where the neutrino detector was constructed in a tunnel protected from cosmic rays by a 300 MWE rock overburden.
TL;DR: The purpose of this work was to develop an efficient method for the production of adeno-associated virus (AAV) vectors in the absence of helper virus, and the minimum set of genes required to produce AAV helper activity equivalent to that provided by adenovirus infection.
Abstract: The purpose of this work was to develop an efficient method for the production of adeno-associated virus (AAV) vectors in the absence of helper virus. The adenovirus regions that mediate AAV vector replication were identified and assembled into a helper plasmid. These included the VA, E2A and E4 regions. When this helper plasmid was cotransfected into 293 cells, along with plasmids encoding the AAV vector, and rep and cap genes, AAV vector was produced as efficiently as when using adenovirus infection as a source of help. CMV-driven constructs expressing the E4orf6 and the 72-M(r), E2A proteins were able to functionally replace the E4 and E2A regions, respectively. Therefore the minimum set of genes required to produce AAV helper activity equivalent to that provided by adenovirus infection consists of, or is a subset of, the following genes: the E4orf6 gene, the 72-M(r), E2A protein gene, the VA RNA genes and the E1 region. AAV vector preparations made with adenovirus and by the helper virus-free method were essentially indistinguishable with respect to particle density, particle to infectivity ratio, capsimer ratio and efficiency of muscle transduction in vivo. Only AAV vector preparations made by the helper virus-free method were not reactive with anti-adenovirus sera.
TL;DR: In this article, the authors used travel diary data for southern California residents to examine the link between land-use patterns at the neighbourhood level and non-work trip generation for a sample of 769 individuals.
Abstract: Planners are increasingly viewing land-use policy as a way to manage transport demand. Yet the evidence on the link between land use and travel behaviour is inconclusive. This paper uses travel diary data for southern California residents to examine the link between land-use patterns at the neighbourhood level and non-work trip generation for a sample of 769 individuals. The number of non-work automobile trips that an individual makes in a two-day period is modelled as a function of socio-demographic variables and land-use characteristics near the person's place of residence. The land-use variables are statistically insignificant in all but one of the specifications. The results suggest that choices about how to measure the variables and how to specify the regressions can influence the conclusions from these studies in potentially important ways. This underscores the need for continued careful attention to these research issues.
TL;DR: A powerful method for identifying and characterizing the effect of attention on performance in visual tasks as due to signal enhancement, distractor exclusion, or internal noise suppression is developed and tested.
TL;DR: Plasticity in the weights between basic visual channels and decision is sufficient to account for perceptual learning without requiring the retuning of visual mechanisms.
Abstract: To investigate the nature of plasticity in the adult visual system, perceptual learning was measured in a peripheral orientation discrimination task with systematically varying amounts of external (environmental) noise. The signal contrasts required to achieve threshold were reduced by a factor or two or more after training at all levels of external noise. The strong quantitative regularities revealed by this novel paradigm ruled out changes in multiplicative internal noise, changes in transducer nonlinearites, and simple attentional tradeoffs. Instead, the regularities specify the mechanisms of perceptual learning at the behavioral level as a combination of external noise exclusion and stimulus enhancement via additive internal noise reduction. The findings also constrain the neural architecture of perceptual learning. Plasticity in the weights between basic visual channels and decision is sufficient to account for perceptual learning without requiring the retuning of visual mechanisms.
TL;DR: A two-compartment model of the lungs is developed in an effort to explain several fundamental experimental observations of endogenous NO exchange and predicts that these relationships can be explained by significant contributions of NO in the exhaled breath from the nonexpansile airways and the expansile alveoli.
Abstract: The relatively recent detection of nitric oxide (NO) in the exhaled breath has prompted a great deal of experimentation in an effort to understand the pulmonary exchange dynamics. There has been very little progress in theoretical studies to assist in the interpretation of the experimental results. We have developed a two-compartment model of the lungs in an effort to explain several fundamental experimental observations. The model consists of a nonexpansile compartment representing the conducting airways and an expansile compartment representing the alveolar region of the lungs. Each compartment is surrounded by a layer of tissue that is capable of producing and consuming NO. Beyond the tissue barrier in each compartment is a layer of blood representing the bronchial circulation or the pulmonary circulation, which are both considered an infinite sink for NO. All parameters were estimated from data in the literature, including the production rates of NO in the tissue layers, which were estimated from expe...
TL;DR: At a median follow-up of 1.1 years, combination prophylaxis with lamivudine and HBIG prevented hepatitis B recurrence following liver transplantation.
TL;DR: Black carbon enters the ocean through aerosol and river deposition and is likely older because it is stored in an intermediate reservoir before sedimentary deposition, which means the importance of riverine carbon in the ocean carbon cycle has been underestimated.
Abstract: Black carbon (BC) enters the ocean through aerosol and river deposition. BC makes up 12 to 31 percent of the sedimentary organic carbon (SOC) at two deep ocean sites, and it is 2400 to 13,900 carbon-14 years older than non-BC SOC deposited concurrently. BC is likely older because it is stored in an intermediate reservoir before sedimentary deposition. Possible intermediate pools are oceanic dissolved organic carbon (DOC) and terrestrial soils. If DOC is the intermediate reservoir, then BC is 4 to 22 percent of the DOC pool. If soils are the intermediate reservoir, then the importance of riverine carbon in the ocean carbon cycle has been underestimated.
TL;DR: It is shown that the proposed scheme provides small handoff dropping probability (i.e., the probability that handoff connections are dropped due to a lack of bandwidth) and achieves high bandwidth utilization.
Abstract: In the next generation high-speed wireless networks, it is important to provide quality-of-service (QoS) guarantees as they are expected to support multimedia applications. This paper proposes an admission control scheme based on adaptive bandwidth reservation to provide QoS guarantees for multimedia traffic carried in high-speed wireless cellular networks. The proposed scheme allocates bandwidth to a connection in the cell where the connection request originates and reserves bandwidth in all neighboring cells. When a user moves to a new cell and a handoff occurs, bandwidth is allocated in the new cell, bandwidth is reserved in the new cell's neighboring cells, and reserved bandwidth in more distant cells is released. The amount of bandwidth to reserve is dynamically adjusted, reflecting the current network conditions. The performance of the proposed scheme is evaluated through simulations of realistic cellular environments. The simulated network consists of a large number of cells, mobile users with various movement patterns are assumed, and a variety of multimedia applications (e.g., audio phone, video conference, video on demand, file transfer, etc.) is considered. It is shown that the proposed scheme provides small handoff dropping probability (i.e., the probability that handoff connections are dropped due to a lack of bandwidth) and achieves high bandwidth utilization.