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Enhanced KOCED Routing Protocol with K-means Algorithm

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Computers, Materials & Continua 2021年第6期67卷 4019-4037页

作者： SeaYoung Park jong-Yong lee Daesung lee Department of Plasma Bioscience and Display KwangWoon University Graduate SchoolSeoul01897Korea Ingenium College of Liberal Arts KwangWoon UniversitySeoulKorea Department of Computer Engineering Catholic University of PusanBusanKorea

Replacing or recharging batteries in the sensor nodes of a wireless sensor network(WSN)is a significant ***,efficient power utilization by sensors is a critical requirement,and it is closely related to the life span of the *** a sensor node consumes all its energy,it will no longer function ***,various protocols have been proposed to minimize the energy consumption of sensors and thus prolong the network ***,clustering algorithms combined with artificial intelligence have been proposed for this *** particular,various protocols employ the K-means clustering algorithm,which is a machine learning *** number of clustering configurations required by the K-means clustering algorithm is greater than that required by the hierarchical ***,the selection of the cluster heads considers only the residual energy of the nodes without accounting for the transmission distance to the base *** terms of energy consumption,the residual energy of each node,the transmission distance,the cluster head location,and the central relative position within the cluster should be considered *** this paper,we propose the KOCED(K-means with Optimal clustering for WSN considering Centrality,Energy,and Distance)protocol,which considers the residual energy of nodes as well as the distances to the central point of the cluster and the base station.A performance comparison shows that the KOCED protocol outperforms the LEACH protocol by 259%(223 rounds)for first node dead(FND)and 164%(280 rounds)with 80%alive nodes.

关键词： WSN routing protocol K-means K-optimal LEACH KCE KOCED

Effect of In Composition on Two-Dimensional Electron Gas in Wurtzite AlGaN/InGaN Heterostructures

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Chinese Physics Letters 2010年第11期27卷 188-190页

作者： KIM Bong-hwan PARK Seoung-hwan lee Jung-Hee MOON Yong-Tae Department of Electronics Engineering Catholic University of Daegu Hayang Kyeongsan Kyeongbuk 712-702 R. Korea School of Electrical Engineering and Computer Science Kyungpook National University Daegu 702-701 R. Korea LG Corporate Institute of Technology 16 Woomyeon-dong Seocho-gu Seoul 137-14-0 R. Korea

The effect of In composition on two-dimensional electron gas in wurtzite AlGaN/InGaN heterostructures is theoretically investigated. The sheet carrier density is shown to increase nearly linearly with In mole fraction x, due to the increase in the polarization charge at the AlGaN/InGaN interface. The electron sheet density is enhanced with the doping in the AlGaN layer. The sheet carrier density is as high as 3.7×1013 cm^-2 at the donor density of 10×1018 cm^-3 for the HEMT structure with x=0.3. The contribution of additional donor density on the electron sheet density is nearly independent of the In mole fraction.

关键词： Condensed matter: electrical magnetic and optical Electronics and devices Semiconductors Surfaces interfaces and thin films Condensed matter: structural mechanical & thermal Nanoscale science and low-D systems

Permeability evaluation for artificial single rock fracture according to geometric aperture variation using electrical resistivity

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第4期13卷 787-797页

作者： Hangbok lee jong-Won lee Tae-Min Oh Deep Subsurface Research Center Korea Institute of Geoscience and Mineral ResourcesDaejeon34132Republic of Korea Department of Civil and Environmental Engineering Pusan National UniversityBusan46241Republic of Korea

A convenient approach was proposed by which to evaluate and monitor the permeability of a rock fracture by verifying the quantitative correlation between the electrical resistivity and permeability at laboratory *** this purpose,an electrical resistivity measurement system was applied to the laboratory experiments using artificial cells with the shape of a single rock *** experiments were conducted using rock fractures according to the geometry,aperture sizes,wavelengths,and roughness *** overall negative relationship between the normalized electrical resistivity values and the aperture sizes directly linked with the permeability,was well fitted by the power-law function with a large determination coefficient(≈0.86).The effects of wavelength and roughness amplitude of the rock fracture on the electrical resistivity were also *** showed that the electrical resistivity was slightly increased with decreasing wavelength and increasing roughness *** empirical model for evaluating the permeability of a rock fracture was proposed based on the experimental *** the field,if the electrical resistivity of pore groundwater could be measured in advance,this empirical model could be applied effectively for simple,quick monitoring of the fracture *** uncertainty may be associated with the permeability estimation due to the limited control parameters considered in this research,this electrical resistivity approach could be helpful to monitor the rock permeability in deep underground facilities such as those used for radioactive waste repositories or forms of energy storage.

关键词： Permeability Rock fracture Electrical resistivity Fracture geometry Long-term monitoring

Characteristics of Sea Breeze Front Development with Various Synoptic Conditions and Its Impact on Lower Troposphere Ozone Formation

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Advances in Atmospheric Sciences 2013年第5期30卷 1461-1478页

作者： Hyo-Eun JI Soon-hwan lee Hwa-Woon lee Division of Earth Environmental System Pusan National University Department of Earth Science Education Pusan National University

To examine the correlation between the sizes of sea breeze fronts and pollutants under the influence of synoptic fields, a numerical simulation was conducted in the southeast coastal area of the Korean Peninsula, where relatively high concentrations of pollutants occur because of the presence of various kinds of industrial developments. Sea breeze and sea breeze front days during the period 2005 09 were identified using wind profiler data and, according to the results, the number of days were 72 and 53, respectively. When synoptic forcing was weak, sea breeze fronts moved fast both in horizontal fields and in terms of wind velocity, while in the case of strong synoptic forcing, sea breeze fronts remained at the coast or moved slowly due to strong opposing flows. In this case, the sea breeze front development function and horizontal potential temperature difference were larger than with weak synoptic forcing. The ozone concentration that moves together with sea breeze fronts was also formed along the frontal surfaces. Ozone advection and diffusion in the case of strong synoptic forcing was suppressed at the frontal surface and the concentration gradient was large. The vertical distribution of ozone was very low due to the Thermal Internal Boundary Layer （TIBL） being low.

关键词： sea breeze front synoptic opposing flow wind profiler ozone numerical simulation

Nanoscale resistive switching devices for memory and computing applications

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Nano Research 2020年第5期13卷 1228-1243页

作者： Seung hwan lee Xiaojian Zhu Wei D.Lu Department of Electrical Engineering and Computer Science The University of MichiganAnn ArborMichigan 48109USA

With the slowing down of the Moore’s law and fundamental limitations due to the von-Neumann bottleneck,continued improvements in computing hardware performance become increasingly more *** switching(RS)devices are being extensively studied as promising candidates for next generation memory and computing applications due to their fast switching speed,excellent endurance and retention,and scaling and three-dimensional(3D)stacking *** particular,RS devices offer the potential to natively emulate the functions and structures of synapses and neurons,allowing them to efficiently implement neural networks(NNs)and other in-memory computing systems for data intensive applications such as machine learning *** this review,we will examine the mechanisms of RS effects and discuss recent progresses in the application of RS devices for memory,deep learning accelerator,and more faithful brain-inspired computing *** and possible solutions at the device,algorithm,and system levels will also be discussed.

关键词： resistive switching oxygen vacancy metal cation memory application in-memory computing bio-inspired application

Synthesis of tin nanoparticles through modified polyol process and effects of centrifuging and drying on nanoparticles

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中国有色金属学会会刊：英文版 2012年第S3期22卷 707-711页

作者： Sang-Soo CHEE jong-Hyun lee Department of Materials Science and Engineering Seoul National University of Science and Technology

Sn nanoparticles with average diameter of 13.1 nm were synthesized by modified polyol process,and their melting point was observed to be about 40 °C less than that of bulk *** though Sn nanoparticles are solid and covered with thin PVP capping and oxide layer,Sn nanoparticles in solution agglomerate upon centrifugation,resulting in a melting point *** to stickiness of the PVP capping layer,extensive aggregation between Sn nanoparticles was observed after ***,the aggregation behavior did not further influence the melting point,because actual agglomeration did not occur in the aggregates.

关键词： tin nanoparticle melting point centrifugation agglomeration aggregation

Nielsen coincidence theory on infra-solvmanifolds of Sol

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Science China Mathematics 2021年第8期64卷 1861-1884页

作者： jong Bum lee Karen Regina Panzarin Department of Mathematics Sogang UniversitySeoul 121-742Korea Departamento de Matematica Universidade Federal de Sao CarlosSao CarlosSP 13565-905Brazil

We derive averaging formulas for the Lefschetz coincidence numbers,the Nielsen coincidence numbers and the Reidemeister coincidence numbers of maps on infra-solvmanifolds modeled on a connected and simply connected solvable Lie group of type(R).As an application,we compare our formula for the Nielsen coincidence numbers with a result of Jezierski(1992)for pairs of maps on some infra-solvmanifolds of *** all the pairs of self-maps of a nonorientable infra-solvmanifold of Sol,we determine the sets of all the possible values of the Nielsen coincidence numbers and the Reidemeister coincidence numbers.

关键词： averaging formula infra-solvmanifold Lefschetz coincidence number Nielsen coincidence number Reidemeister coincidence number Sol-geometry

Assessment criteria for nonverbal interaction contents in r-learning

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Journal of Central South University 2013年第9期20卷 2388-2398页

作者： CHOI jong-hong lee jong-yun YOON Heung-seob Department of Computer Education Chungbuk National University Department of English Education Chungbuk National University

r-learning,which is based on e-learning and u-learning,is defined as a learning support system that intelligent robots serve verbal and nonverbal interactions on ubiquitous computing *** order to guarantee the advantages of r-learning contents with no limits of timc and place and with nonverbal interaction which are not in e-learning contents,in recent years,assessment criteria for r-learning contents are urgently ***,the reliable and valid assessment criteria were developed for nonverbal interaction contents in r-learning,and its detailed research content is as ***,assessment criteria for nonverbal interaction in r-learning contents will be specified into gesture,facial expression,semi-verbal message,distance,physical contact and ***,the validity of the developed assessment criteria will be proved by ***,the assessment criteria for nonverbal interaction contents will be helpful when choosing the better r-learning content and producing the better r-learning content,and the reliability of school education is improved ultimately.

关键词： r-learning, r-learning contents assessment criteria nonverbal interaction contents confirmatory factor analysis construct validity

Effect of electrical stimulation on neural regeneration via the p38-RhoA and ERK1/2-Bcl-2 pathways in spinal cord-injured rats

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Neural Regeneration Research 2018年第2期13卷 340-346页

作者： Min Cheol Joo Chul hwan Jang jong Tae Park Seung Won Choi Seungil Ro Min Seob Kim Moon Young lee Department of Rehabilitation Medicine and Institute of Wonkwang Medical Science School of Medicine Wonkwang University Department of Neurosurgery School of Medicine Wonkwang University Department of Anesthesiology and Pain Medicine School of Medicine Wonkwang University Department of Physiology and Cell Biology School of Medicine University of Nevada Department of Physiology and Institute of Wonkwang Medical Science School of Medicine Wonkwang University

Although electrical stimulation is therapeutically applied for neural regeneration in patients, it remains unclear how electrical stimulation exerts its effects at the molecular level on spinal cord injury （SCI）. To identify the signaling pathway involved in electrical stimulation improving the function of injured spinal cord, 21 female Sprague-Dawley rats were randomly assigned to three groups： control （no surgical intervention, n = 6）, SCI （SCI only, n = 5）, and electrical simulation （ES; SCI induction followed by ES treatment, n = 10）. A complete spinal cord transection was performed at the 10^th thoracic level. Electrical stimulation of the injured spinal cord region was applied for 4 hours per day for 7 days. On days 2 and 7 post SCI, the Touch-Test Sensory Evaluators and the Basso-Beattie-Bresnahan locomotor scale were used to evaluate rat sensory and motor function. Somatosensory-evoked potentials of the tibial nerve of a hind paw of the rat were measured to evaluate the electrophysiological function of injured spinal cord. Western blot analysis was performed to measure p38-RhoA and ERK1/2-Bcl-2 pathways related protein levels in the injured spinal cord. Rat sensory and motor functions were similar between SCI and ES groups. Com- pared with the SCI group, in the ES group, the latencies of the somatosensory-evoked potential of the tibial nerve of rats were significantly shortened, the amplitudes were significantly increased, RhoA protein level was significantly decreased, protein gene product 9.5 expression, ERK1/2, p38, and Bcl-2 protein levels in the spinal cord were significantly increased. These data suggest that ES can promote the recovery of electrophysiological function of the injured spinal cord through regulating p38-RhoA and ERK1/2-Bcl-2 pathway-related protein levels in the injured spinal cord.

关键词： Bcl-2 ERKI/2 p38 PGP9.5 RhoA spinal cord injury somatosensory evoked potential muscle contraction electrical impulses neural regeneration