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Search Results: 1 - 10 of 62354 matches for " Sung-Bong Yang "
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Effective Location Acquisition Control Algorithms for the Location-Based Alert Services in Mobile Environments
So-Young Kang,Kwang-Jo Lee,Sung-Bong Yang
International Journal of Computer Networks & Communications , 2010,
Abstract: The location-based alert services can be regarded as the one of the most practical locationbasedservices. For the services, an alert service system for the services alerts mobile device users whenthey enter into or leave from predefined specific regions, and provides certain services previously askedby the users for special purposes such as security. For providing proper services the alert service systemshould acquire the location information of the users periodically. However, the system that handles thelocations of the users may face serious problems as the number of users increases fast. Hence it is acritical issue to properly adjust the time interval of location data acquisitions while maintaining theaccuracy of the services. In this paper we propose effective location acquisition algorithms; the speedbasedacquisition algorithm, the angle–based acquisition algorithm, and the hybrid algorithm combiningthe speed with the angle-based algorithms. We also present three grid-based acquisition algorithms inwhich a longer time interval is used when a user is not near the alert areas. The proposed algorithmscould reduce the amount of location information to be acquired based on the movement of the users. Theaverage numbers of location acquisitions of the speed-based, the angle–based, and the hybrid algorithmswere reduced by 19.2%, 35.8%, and 35.6% over the distance-based algorithm, respectively, while theymaintained the almost same level of accuracy. Among the grid-based algorithms, the grid-angleacquisition algorithm further improved the average number of acquisitions by 5.2% over the angle-basedalgorithm, which is 41.0% improvement over the distance-based algorithm. The experimental results alsoshow that all the grid-based algorithms showed almost equal accuracy.
EFFECTIVE REPLICATED SERVER ALLOCATION ALGORITHMS IN MOBILE COMPUTING SYSTEMS
Jin-Woo Song,Kwang-Jo Lee,Taek-Hun Kim,Sung-Bong Yang
International Journal of Wireless & Mobile Networks , 2009,
Abstract: In mobile environments, mobile device users access and transfer a great deal of data through the online servers. In order to enhance users’ access speed in a wireless network, decentralizing replicated servers appropriately in the network is required. Previous work regarding this issue had focused on the placement of replicated servers along with the moving paths of the users to maximize the hit ratio. When a miss occurs, they simply ignored the file request. Therefore, we suggest a solution to take care of such a miss by sending a file request to a replicated server nearby in the network.This paper is to propose new cost-effective wireless access algorithms incorporating a present replicated server allocation algorithm with more keen analysis of the moving patterns of mobile device users. We propose four different algorithms that allocate available replicated servers in the network so as tominimize the communication costs. The experimental results show that, among the proposed algorithms, the replicated server clustering algorithm allocated replicated servers with near optimal communicationcosts.
A Possible Mechanism Underlying the Effectiveness of Acupuncture in the Treatment of Drug Addiction
Chae Ha Yang,Bong Hyo Lee,Sung Hoon Sohn
Evidence-Based Complementary and Alternative Medicine , 2008, DOI: 10.1093/ecam/nem081
Abstract: Clinical trials are currently underway to determine the effectiveness of acupuncture in the treatment of drug addiction. While there are still many unanswered questions about the basic mechanisms of acupuncture, some evidence exists to suggest that acupuncture can play an important role in reducing reinforcing effects of abused drugs. The purpose of this article is to critically review these data. The neurochemical and behavioral evidence showed that acupuncture's role in suppressing the reinforcing effects of abused drugs takes place by modulating mesolimbic dopamine neurons. Also, several brain neurotransmitter systems such as serotonin, opioid and amino acids including GABA have been implicated in the modulation of dopamine release by acupuncture. These results provided clear evidence for the biological effects of acupuncture that ultimately may help us to understand how acupuncture can be used to treat abused drugs. Additional research using animal models is of primary importance to understanding the basic mechanism underlying acupuncture's effectiveness in the treatment of drug addiction.
A Cancer Specific Cell-Penetrating Peptide, BR2, for the Efficient Delivery of an scFv into Cancer Cells
Ki Jung Lim, Bong Hyun Sung, Ju Ri Shin, Young Woong Lee, Da Jung Kim, Kyung Seok Yang, Sun Chang Kim
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0066084
Abstract: Cell-penetrating peptides (CPPs) have proven very effective as intracellular delivery vehicles for various therapeutics. However, there are some concerns about non-specific penetration and cytotoxicity of CPPs for effective cancer treatments. Herein, based on the cell-penetrating motif of an anticancer peptide, buforin IIb, we designed several CPP derivatives with cancer cell specificity. Among the derivatives, a 17-amino acid peptide (BR2) was found to have cancer-specificity without toxicity to normal cells. After specifically targeting cancer cells through interaction with gangliosides, BR2 entered cells via lipid-mediated macropinocytosis. Moreover, BR2 showed higher membrane translocation efficiency than the well-known CPP Tat (49–57). The capability of BR2 as a cancer-specific drug carrier was demonstrated by fusion of BR2 to a single-chain variable fragment (scFv) directed toward a mutated K-ras (G12V). BR2-fused scFv induced a higher degree of apoptosis than Tat-fused scFv in K-ras mutated HCT116 cells. These results suggest that the novel cell-penetrating peptide BR2 has great potential as a useful drug delivery carrier with cancer cell specificity.
Transcortical Alterations in - ATPase and Microtubule-Associated Proteins Immunoreactivity in the Rat Cortical Atrophy Model Induced by Hypoxic Ischemia
Jun-Gyo Suh,Sung-Jin An,Jae-Bong Park,Zae-Young Ryoo,Jeong Woong Lee,Yang-Seok Oh,Moo Ho Won,Tae-Cheon Kang
Neural Plasticity , 2002, DOI: 10.1155/np.2002.135
Abstract: To identify the chronological transcortical change in the contralateral hemisphere following ischemic insults, we investigated the changes in microtubule associated protein (MAP) and Na
Anti-inflammatory and antiarthritic effects of piperine in human interleukin 1β-stimulated fibroblast-like synoviocytes and in rat arthritis models
Jun Soo Bang, Da Hee Oh, Hyun Mi Choi, Bong-Jun Sur, Sung-Jig Lim, Jung Yeon Kim, Hyung-In Yang, Myung Chul Yoo, Dae-Hyun Hahm, Kyoung Soo Kim
Arthritis Research & Therapy , 2009, DOI: 10.1186/ar2662
Abstract: The in vitro anti-inflammatory activity of piperine was tested on interleukin 1β (IL1β)-stimulated fibroblast-like synoviocytes derived form patients with rheumatoid arthritis. The levels of IL6, matrix metalloproteinase (MMPs), cyclo-oxygenase 2 (COX-2), and prostaglandin E2 (PGE2) were investigated by ELISA and RT-PCR analysis. The analgesic and antiarthritic activities of piperine were investigated on rat models of carrageenan-induced acute paw pain and arthritis. The former were evaluated with a paw pressure test, and the latter by measuring the squeaking score, paw volume, and weight distribution ratio. Piperine was administrated orally to rats at 20 and 100 mg/kg/day for 8 days.Piperine inhibited the expression of IL6 and MMP13 and reduced the production of PGE2 in a dose dependant manner at concentrations of 10 to 100 μg/ml. In particular, the production of PGE2 was significantly inhibited even at 10 μg/ml of piperine. Piperine inhibited the migration of activator protein 1 (AP-1), but not nuclear factor (NF)κB, into the nucleus in IL1β-treated synoviocytes. In rats, piperine significantly reduced nociceptive and arthritic symptoms at days 8 and 4, respectively. Histological staining showed that piperine significantly reduced the inflammatory area in the ankle joints.These results suggest that piperine has anti-inflammatory, antinociceptive, and antiarthritic effects in an arthritis animal model. Thus, piperine should be further studied with regard to use either as a pharmaceutical or as a dietary supplement for the treatment of arthritis.Rheumatoid arthritis is characterized by chronic proliferative synovitis, inflammatory immune cell infiltration into the synovial fluid and cartilage destruction [1]. Proliferative fibroblast-like synoviocytes (FLSs) play crucial roles in both the propagation of inflammation and joint damage because they produce a great amount of proinflammatory mediators such as matrix metalloproteinses (MMPs), interleukin (IL)6, IL8 and pr
Structural Analysis of Hypothetical Proteins from Helicobacter pylori: An Approach to Estimate Functions of Unknown or Hypothetical Proteins
Sung Jean Park,Woo Sung Son,Bong-Jin Lee
International Journal of Molecular Sciences , 2012, DOI: 10.3390/ijms13067109
Abstract: Helicobacter pylori ( H. pylori) have a unique ability to survive in extreme acidic environments and to colonize the gastric mucosa. It can cause diverse gastric diseases such as peptic ulcers, chronic gastritis, mucosa-associated lymphoid tissue (MALT) lymphoma, gastric cancer, etc. Based on genomic research of H. pylori, over 1600 genes have been functionally identified so far. However, H. pylori possess some genes that are uncharacterized since: (i) the gene sequences are quite new; (ii) the function of genes have not been characterized in any other bacterial systems; and (iii) sometimes, the protein that is classified into a known protein based on the sequence homology shows some functional ambiguity, which raises questions about the function of the protein produced in H. pylori. Thus, there are still a lot of genes to be biologically or biochemically characterized to understand the whole picture of gene functions in the bacteria. In this regard, knowledge on the 3D structure of a protein, especially unknown or hypothetical protein, is frequently useful to elucidate the structure-function relationship of the uncharacterized gene product. That is, a structural comparison with known proteins provides valuable information to help predict the cellular functions of hypothetical proteins. Here, we show the 3D structures of some hypothetical proteins determined by NMR spectroscopy and X-ray crystallography as a part of the structural genomics of H. pylori. In addition, we show some successful approaches of elucidating the function of unknown proteins based on their structural information.
Spontaneously Broken Erlangen Program Offers a Bridge Between the Einstein and the Yang-Mills Theories
Yi Yang,Wai Bong Yeung
Physics , 2012,
Abstract: We shall give dynamics to our spacetime manifold by first identifying the local affine symmetry as the characterizing symmetry for our geometry \'a la Felix Klein, and then by prescribing 16 gauge vector bosons to this symmetry \'a la Yang and Mills. The locally affine symmetric Yang-Mills Lagrangian in the presence of a background world metric, and the corresponding equations of motion, are respectively constructed and derived. Spontaneous breaking of the local affine symmetry to the local Lorentz symmetry is achieved by classical solutions to the equations of motion. In these classical solutions, the 16 gauge vector bosons are shown to select the Schwarzschild metric as one among the admissible background world metrics. Classical gravity is expressed by a spontaneously broken Erlangen program.
Quadratic Gravitational Lagrangian with Torsion Can Give Possible Explanations of the Form of Galactic Rotation Curves, of the Amount of Intergalactic Lensings, and of the Accelerating Expansion of the Universe
Yi Yang,Wai Bong Yeung
Physics , 2011,
Abstract: The Quadratic Gravitational Lagrangian with torsion provides us with a richer number of solutions than the Einstein-Hilbert Lagrangian does. With proper interpretation, these solutions, together, seem to give good explanations of the form of the galactic rotation curves, of the amount of intergalactic gravitational lensings, and of the accelerating expansion of the Universe. The existence of Particle Families can also arise from the existence of these various microscopic metrics endowed to the respective particles
A New Approach to the Yang-Mills Gauge Theory of Gravity and its Applications
Yi Yang,Wai Bong Yeung
Physics , 2013,
Abstract: We shall give dynamics to our spacetime manifold by first identifying the local affine symmetry as the characterizing symmetry for our geometry a'la Felix Klein, this symmetry is imposed on us by the Law of Inertia and the Law of Causality. We then prescribe 16 gauge vector bosons to this symmetry a'la Yang and Mills. The locally affine symmetric Yang-Mills Lagrangian in the presence of a background world metric, and the corresponding equations of motion, are respectively constructed and derived. Spontaneous breaking of the local affine symmetry to the local Lorentz symmetry is achieved by classical solutions to the equations of motion. In these classical solutions, the 16 gauge vector bosons are shown to select the Schwarzschild metric as one among the admissible background world metrics. Classical gravity is thus be expressed by a spontaneously broken Erlangen program. We shall also show that this Yang-Mills gauge theory of gravity can give an explanation of the form of the galactic rotation curves, of the amount of intergalactic gravitational lensing, and of the accelerating expansion of the Universe.
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