• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.5 s.347
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• pp.113-120
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• 2006

This thesis deals with solutions such as coverage area extension, reduction of the shadow region and performance enhancement of handover caused by structural modification of WiBro network. The More far the distance of RAS(Radio Access Station) and SS(Subscriber Station) is in micro cell, the more bad the quality of channel environment becomes owing to radio interference. Consequently, it causes the deterioration of the throughput and also the deterioration of communication quality in many sides. In fact, most users of WiBro are located in the region, the QPSK region which is bad in point of channel quality. It brings the service complaint by user. We select RS(relay station) to solve the matter caused by channel environment in this cell, and extend coverage and improve the performance of handover call blocking.

• Journal of Internet Computing and Services
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• v.11 no.3
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• pp.43-51
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• 2010

In this paper, we evaluate the system throughput and the method of optimal wireless resource allocation for the access zone (AZ) and relay zone (RZ) in downlink when the cell coverage is extended using the non-transparent Relay Station (RS) in a 2-hop cellular relay system based on IEEE802.16j, which uses the OFDMA-TDD structure. For the analyses, we first introduce the MAC (Media Access Control) frame structure in the non-transparent mode, then we investigate the interfering elements in both AZ and RZ for the network devices such as the Mobile Station (MS) and RS. Through computer simulation, we analyze the cell coverage extension and system throughput in terms of the distance between Base Station (BS) and RS, then we present the amount of the optimal allocation of wireless resource for the AZ and RZ in downlink using our results.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.7
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• pp.72-79
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• 2010

Device-to-device(D2D) links which share resources in a cellular network present a challenge in radio resource management due to the potentially severe interference they may cause to the cellular network. In this paper, a resource allocation scheme based on subset reuse methods is proposed to minimize the interference from the D2D links. We consider an adaptive group-wise subset reuse method to enhance the efficiency of frequency resource allocation for cellular and D2D links. A power optimization scheme is also proposed for D2D links if cellular links are interfered by adjacent D2D transmissions. The computer simulation results show that performance gain is obtained in link SINR, and total cell throughput increases as nearby traffic becomes more dominant.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.7 s.361
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• pp.47-52
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• 2007

This paper analyzes the output signal-to-interference-plus-noise ratio (SINR) for a multiple-input-multiple-output (MIMO) multicarrier code division multiple access (MC-CDMA) system with minium mean square error receivers in multi-cell environments. A previous work in single cell environments is extended into analysis in multi-cell environments. The use of Haar unitary code matrix for asymptotic analysis causes other cell interferences expressed with a diagonal matrix haying different diagonal values. This paper shows that other cell interferences converge to an identity matrix whose gain is expressed by only other cell interference power in mean square sense and finds asymptotic deterministic SINRs for a given other cell interference. Under the assumption that the sum of lognormal fading components is distributed by other lognormal function, we show the comparison between theoretical performances and simulations from the view point of bit error rate and present average throughput performance according to the cell radius.

• Proceedings of the Microbiological Society of Korea Conference
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• 2005.05a
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• pp.28-32
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• 2005

Epifluorescence microscopy and direct viable counting methods have shown that only 0.01-0.1% of all the microbial cells from marine environments form colonies on standard agar plates. To culture novel marine microorganisms, high throughput culturing (HTC) techniques were developed to isolate cells in very low nutrient media. This approaches was designed to address microbial metabolic precesses that occur at natural substrate concentrations and cell densities, which are typically about three orders of magnitude less than in common laboratory media. Approximately 5000 cultures of pelagic marine bacteria were examined over the course of 3 years. Up to 14% of cells from coastal seawater were cultured using this method, a number that is 1400 to 140-fold higher than obtained by traditional microbiological culturing techniques. Among the cultured organisms are many unique phylogenetic lineages that have been named as new phyla (7), orders (2, 5, 12), families (3), and genera (1, 4, 6). Over 90% of the cells recovered by this method do not replicate in standard agar plating, the most common method of microbial cell cultivation.

• Journal of Communications and Networks
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• v.8 no.4
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• pp.422-431
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• 2006

This paper proposes an adaptive routing protocol called ARCA for converged ad-hoc and cellular network (CACN). Due to the limitation of both bandwidth and transmission range in a cell, a mobile host (MH) may not be able to make a call during busy time. CACN offers a flexible traffic diversion mechanism that allows a MH to use the bandwidth in another cell to ease the congestion problem and increase the throughput in a cellular network. Based on the presentation of CACN's physical characteristics, the paper details the design issues and operation of the adaptive routing protocol for CACN (ARCA). Detailed numerical analysis is presented in terms of both route request rejection rate and routing overhead, which, along with the simulation results, have indicated the effectiveness and efficiency of the ARCA protocol.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.251-252
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• 2008

Throughput and quality-of-service (QoS) over multi-cell environments are two of the most challenging issues that must be addressed when developing next generation wireless network standards. Currently, multiple-input/multiple-output (MIMO), inter-cell coordination and multi-hop relay technologies are viable options for improving channel capacity or coverage extension. Nevertheless, severe QoS degradation occurs in the outer region of multi-cells due to significant interference from neighboring cells or relay stations, thereby limiting overall performance. Therefore, we propose a scheme which adapted to hybrid relaying.

• Journal of Genetic Medicine
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• v.12 no.2
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• pp.66-71
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• 2015

Down syndrome screening with cell-free DNA (cfDNA) in the maternal plasma has recently received much attention in the prenatal diagnostic field. Indeed, a large amount of evidence has already accumulated to show that screening tests with cfDNA are more sensitive and specific than conventional maternal serum and/or ultrasound screening. Globally, more than 1,000,000 of these noninvasive prenatal tests (NIPTs) have been performed to date. There are several different methods for NIPTs that are currently commercially available, including shotgun massively parallel sequencing, targeted massively parallel sequencing, and single nucleotide polymorphism (SNP)-based methods. All of these methods have their own advantages and disadvantages. In this review, I will focus specifically on the SNP-based NIPT.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.12
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• pp.4356-4371
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• 2014

When the load in a multi-cell orthogonal frequency division multiple access (OFDMA) system is allowed to excessively increase in face of frequent handover, the cell area becomes smaller than the designed size, and thus continuity of quality of service (QoS) for handover requests cannot be guaranteed. To efficiently support the mobility of a mobile terminal (MT), we should adaptively cope with the resource demand of handover calls. This paper proposes a twofold resource-reservation scheme for OFDMA systems to guarantee continuity of QoS for various mobile multimedia services during MT handover from lightly to heavily loaded cells. Our twofold scheme attempts to guarantee service continuity for handover and to maximize resource allocation efficiency. We performed a simulation to evaluate our scheme in terms of outage probability, handover failure rate, total throughput, and blocking rate.

• Bulletin of the Korean Chemical Society
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• v.23 no.7
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• pp.1003-1010
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• 2002

Caspase 3, a member of cysteine protease family, is well known as a major apoptosis effector and is involved in cell death as a result of ischemic diseases such as stroke and myocardial infarction, therefore the inhibition of caspase 3 may protect those apoptotic cell damages. During the high-throughput screening of the compounds from the Korea Chemical Bank, berberine derivatives (A and B), an isoquinoline alkaloid, have been identified as potential inhibitors for caspase 3. Based on this finding we carried out molecular modeling study to identify the pharmacophoric elements of berberine structure which interact with a substrate-recognition binding site of caspase 3 and came up with several novel scaffolds. In this report, we will discuss the molecular modeling, syntheses and the enzyme inhibitory activities of these novel compounds.