• Title/Summary/Keyword: Cellular capacity

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Location Area Design of a Cellular Network with Time-dependent Mobile flow and Call Arrival Rate (시간에 따른 인구유동/호 발생의 변화를 고려한 이동통신 네트워크의 위치영역 설계)

  • Hong Jung-Sik;Jang Jae-Song;Kim Ji-Pyo;Lie Chang-Hoon;Lee Jin-Seung
    • Journal of the Korean Operations Research and Management Science Society
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    • v.30 no.3
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    • pp.119-135
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    • 2005
  • Design of location erea(LA) in a cellular network is to partition the network into clusters of cells so as to minimize the cost of location updating and paging. Most research works dealing with the LA design problem assume that the call. arrival rate and mobile flow rate are fixed parameters which can be estimated independently. In this aspect, most Problems addressed so far are deterministic LA design problems(DLADP), known to be NP hard. The mobile flow and call arrival rate are, however, varying with time and should be treated simultaneously because the call arrival rate in a cell during a day is influenced by the change of a population size of the cell. This Paper Presents a new model on IA design problems considering the time-dependent call arrival and mobile flow rate. The new model becomes a stochastic LA design problem(SLADP) because It takes into account the possibility of paging waiting and blocking caused by the changing call arrival rate and finite paging capacity. Un order to obtain the optimal solution of the LA design problem, the SIADP is transformed Into the DLADP by introducing the utilization factor of paging channels and the problem is solved iteratively until the required paging quality is satisfied. Finally, an illustrative example reflecting the metropolitan area, Seoul, is provided and the optimal partitions of a cell structure are presented.

IMMUNOHISTOCHEMICAL ANALYSIS OF EGFR AND C-ERB-B2 GENE EXPRESSION OF SQUAMOUS CELL CARCINOMA IN ORAL CAVITY (구강 편평세포암에서 EGFR과 C-erb-B2 유전자 발현에 관한 면역조직화학적 연구)

  • Cho, Won;Cho, Jae-Shik;Lee, Chong-Won;Kim, Hae-Song;Park, Guen-Jae
    • Korean Journal of Bronchoesophagology
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    • v.2 no.2
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    • pp.200-212
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    • 1996
  • The clinical staging systems for oral squamous cell carcinoma is limited as a prognostic indicatior because of different biological characteristics of cancer in this region and variable microenvironment depending on subsites, there have been study to determine prognosis by evaluating malignancy, that is the nature of tumor cells. Many studies have been tried to determine prognostic indicator in various malignancies for the evaluation of differentiation capacity and the expression of oncogene product. EGF make a role in cellular growth and differentiation and to be essential in cellular survival. EGFR is an intergral membrane protein, stimulate cellular differentiation and hormonal secretion, and has structural homology with V-erb-B transforming protein. Recent reports have demonstrated that EGFR is overexpressed in stomach, breast, vagina, dermis, head and neck, genitourinary and lung tumors, and possibly used as a tumor marker. In head and neck region, most of studies were mainly carried out on laryngeal squamous cell carcinoma. In the present study, immunohistochemical study for EGFR and C-erb-B2 gene in paraffin sections of 45 squamous cell carcinoma in oral cavity was performed to evaluate the presense of EGFR and C- erb-B2 gene in this lesion, to evaluate them as a prognostic indicator by analysing the correlation between these expression and subsites, primary stages, clinical stages, pathologic grades, neck node metastasis, recurrences and treatment results, and to determine relation between EGFR and C-erb-B2 gene.

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An Efficient Inter-Cell Interference Mitigation Scheme for Proximity Service in Cellular Networks (셀룰러 망에서 Proximity Service를 위한 효율적인 셀 간 간섭 완화 방안)

  • Kim, Cha-Ju;Min, Sang-Won
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.17 no.1
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    • pp.100-113
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    • 2018
  • The Proximity Service, which is one of the most popular network capacity improvement methods, uses the frequency reuse in order to increase the frequency efficiency. As a result, inter-cell interference between cellular and proximity service users occurs at a cell edge. In this paper, we proposed a mitigation scheme for inter-cell interference, where we suggested a new function of and eNB with ProSe function exchanging information about ProSe parameters and ProSe user equipment with neighboring cells via the X2 interface. As the first step, the resource which did not cause the inter-cell interference problem were pre-allocated through the frequency sensing in the ProSe direct discovery. As the next step, the inter-cell interference problem was solved by reallocating appropriate resources based on the ProSe application code, the ProSe application QoS, the ProSe application ID and validity timer in ProSe direct communication.

Spectrum Reuse Schemes with Power Control for Device-to-Device Communication in LTE-Advanced Cellular Network

  • Chhorn, Sok;Yoon, Seok-Ho;Seo, Si-O;Kim, Seung-Yeon;Cho, Choong-Ho
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.9 no.12
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    • pp.4819-4834
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    • 2015
  • The spectral efficiency of cellular networks can be improved when proximate users engage in device-to-device (D2D) communications to communicate directly without going through a base station. However, D2D communications that are not properly designed may generate interference with existing cellular networks. In this paper, we study resource allocation and power control to minimize the probability of an outage and maximize the overall network throughput. We investigate three power control-based schemes: the Partial Co-channel based Overlap Resource Power Control (PC.OVER), Fractional Frequency Reuse based Overlap Resource Power Control (FFR.OVER) and Fractional Frequency Reuse based Adaptive Power Control (FFR.APC) and also compare their performance. In PC.OVER, a certain portion of the total bandwidth is dedicated to the D2D. The FFR.OVER and FFR.APC schemes combine the FFR techniques and the power control mechanism. In FFR, the entire frequency band is partitioned into two parts, including a central and edge sub-bands. Macrocell users (mUEs) transmit using uniform power in the inner and outer regions of the cell, and in all three schemes, the D2D receivers (D2DRs) transmit with low power when more than one D2DRs share a resource block (RB) with the macrocells. For PC.OVER and FFR.OVER, the power of the D2DRs is reduced to its minimum, and for the FFR.APC scheme, the transmission power of the D2DRs is iteratively adjusted to satisfy the signal to interference ratio (SIR) threshold. The three schemes exhibit a significant improvement in the overall system capacity as well as in the probability of a user outage when compared to a conventional scheme.

Suppression of Cellular Apoptosis Susceptibility (CSE1L) Inhibits Proliferation and Induces Apoptosis in Colorectal Cancer Cells

  • Zhu, Jin-Hui;Hong, De-Fei;Song, Yong-Mao;Sun, Li-Feng;Wang, Zhi-Fei;Wang, Jian-Wei
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.2
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    • pp.1017-1021
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    • 2013
  • The cellular apoptosis susceptibility (CSE1L) gene has been demonstrated to regulate multiple cellular mechanisms including the mitotic spindle check point as well as proliferation and apoptosis. However, the importance of CSE1L in human colon cancer is largely unknown. In the present study, we examined expression levels of CSE1L mRNA by semiquantitative RT-PCR. A lentivirus-mediated small interfering RNA (siRNA) was used to knock down CSE1L expression in the human colon cancer cell line RKO. Changes in CSE1L target gene expression were determined by RT-PCR. Cell proliferation was examined by a high content screening assay. In vitro tumorigenesis was measured by colony-formation assay. Cell cycle distribution and apoptosis were detected by flow cytometric analysis. We found CSE1L mRNA to be expressed in human colon cancer cells. Using a lentivirus based RNAi approach, CSE1L expression was significantly inhibited in RKO cells, causing cell cycle arrest in the G2/M and S phases and a delay in cell proliferation, as well as induction of apoptosis and an inhibition of colony growth capacity. Collectively, the results suggest that silencing of CSE1L may be a potential therapeutic approach for colon cancer.

Performance Evaluation of Device-to-Device Communications Based on System-Level Simulation in Cellular Networks (셀룰라 네트워크 환경에서 시스템 레벨 시뮬레이션 기반 단말간 직접통신 성능 분석)

  • Lee, Howon;Choi, Hyun-Ho;Jung, Soojung;Chang, Sung-Cheol;Kwon, Dong-Seung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38B no.4
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    • pp.229-239
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    • 2013
  • Recently, device-to-device (D2D) communications have been highlighted to improve the spectral efficiency and offer various user experiences in cellular networks. In this paper, we survey standards and literatures related to the D2D technology and address various advantages of D2D technology, and the problems to be resolved before practically implemented. Especially, by considering an important interference issue between cellular and D2D links, five resource allocation and interference management scenarios are provided and their performances are evaluated through the system level simulations. The simulation results show that the use of D2D significantly improve the cell capacity and the D2D user rate due to the effects of frequency reuse and data off-loading. Notably, it is also shown that an optimal D2D communication range exists to maximize the system performance.

The Review of Metabolic Acidosis During Exercise (운동 시 대사적 산성화에 관한 고찰)

  • Yoon, Byung-Kon
    • Journal of the Korean Applied Science and Technology
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    • v.35 no.4
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    • pp.1433-1441
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    • 2018
  • The development of acidosis during intense exercise has traditionally been explained by the increased production of lactic acid which causes the release of a proton and the formation of the acid salt sodium lactate. Through this explanation, when the rate of lactate production is high enough to exceed cellular proton buffering capacity, cellular pH is decreased. This biochemical process has been termed lactic acidosis. This belief has been an interpretation that lactate production causes acidosis and fatigue during intense exercise. However, this review provides clear evidence that there is no biochemical support for lactate production causing acidosis and fatigue. Metabolic acidosis is caused by an increased reliance on nonmitochondrial ATP turnover. Lactate production is essential for muscle to produce cytosolic $NAD^+$ to support continued ATP regeneration from glycolysis. In addition, Lactate production consumes protons. Although lactate accumulation can be a good indirect indicator for decreased cellular and blood pH, that is not direct causing acidosis.

Synthesis of ginsenoside Rb1-imprinted magnetic polymer nanoparticles for the extraction and cellular delivery of therapeutic ginsenosides

  • Liu, Kai-Hsi;Lin, Hung-Yin;Thomas, James L.;Shih, Yuan-Pin;Yang, Zhuan-Yi;Chen, Jen-Tsung;Lee, Mei-Hwa
    • Journal of Ginseng Research
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    • v.46 no.5
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    • pp.621-627
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    • 2022
  • Background: Panax ginseng (ginseng) is a traditional medicine that is reported to have cardioprotective effects; ginsenosides are the major bioactive compounds in the ginseng root. Methods: Magnetic molecularly imprinted polymer (MMIP) nanoparticles might be useful for both the extraction of the targeted (imprinted) molecules, and for the delivery of those molecules to cells. In this work, plant growth regulators were used to enhance the adventitious rooting of ginseng root callus; imprinted polymeric particles were synthesized for the extraction of ginsenoside Rb1 from root extracts, and then employed for subsequent particle-mediated delivery to cardiomyocytes to mitigate hypoxia/reoxygenation injury. Results: These synthesized composite nanoparticles were first characterized by their specific surface area, adsorption capacity, and magnetization, and then used for the extraction of ginsenoside Rb1 from a crude extract of ginseng roots. The ginsenoside-loaded MMIPs were then shown to have protective effects on mitochondrial membrane potential and cellular viability for H9c2 cells treated with CoCl2 to mimic hypoxia injury. The protective effect of the ginsenosides was assessed by staining with JC-1 dye to monitor the mitochondrial membrane potential. Conclusion: MMIPs can play a dual role in both the extraction and cellular delivery of therapeutic ginsenosides.

The Performance Analysis of Cognitive-based Overlay D2D Communication in 5G Networks

  • Abdullilah Alotaibi;Salman A. AlQahtani
    • International Journal of Computer Science & Network Security
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    • v.24 no.2
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    • pp.178-188
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    • 2024
  • In the near future, it is expected that there will be billions of connected devices using fifth generation (5G) network services. The recently available base stations (BSs) need to mitigate their loads without changing and at the least monetary cost. The available spectrum resources are limited and need to be exploited in an efficient way to meet the ever-increasing demand for services. Device to Device communication (D2D) technology will likely help satisfy the rapidly increasing capacity and also effectively offload traffic from the BS by distributing the transmission between D2D users from one side and the cellular users and the BS from the other side. In this paper, we propose to apply D2D overlay communication with cognitive radio capability in 5G networks to exploit unused spectrum resources taking into account the dynamic spectrum access. The performance metrics; throughput and delay are formulated and analyzed for CSMA-based medium access control (MAC) protocol that utilizes a common control channel for device users to negotiate the data channel and address the contention between those users. Device users can exploit the cognitive radio to access the data channels concurrently in the common interference area. Estimating the achievable throughput and delay in D2D communication in 5G networks is not exploited in previous studies using cognitive radio with CSMA-based MAC protocol to address the contention. From performance analysis, applying cognitive radio capability in D2D communication and allocating a common control channel for device users effectively improve the total aggregated network throughput by more than 60% compared to the individual D2D throughput without adding harmful interference to cellular network users. This approach can also reduce the delay.

Effect of Feedstuffs on Mineral Composition, Antioxidant Capacity, and Protection of Neuronal PC-12 Cells of Deer Antlers (녹용의 무기질 조성, 항산화능 및 PC-12 신경 세포 보호능에 대한 급여 사료의 영향)

  • Cho, Chi-Heung;Lee, Bong-Han;Kim, Hae-Yeong;Kim, Young-Chae;Kim, Dae-Ok
    • KSBB Journal
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    • v.27 no.4
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    • pp.243-250
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    • 2012
  • The ash content, mineral composition, total phenolics, antioxidant capacity, and neuroprotective effect of the antlers of deer fed with herb-incorporated feedstuff (HFS) or normal feedstuff (NFS) were comparatively evaluated. The contents of ash and mineral of the antler of deer fed with HFS were significantly lower than its counterpart. The ash and mineral contents of deer antlers decreased generally from the upper section toward the tip section. The ratios of Ca/ash, Ca/P, and Ca/Fe of antler of deer fed with HFS were lower than those of antler of deer fed with NFS. Antlers of deer fed with HFS had higher total phenolics, nitrite scavenging capacity, and antioxidant capacity than those of deer fed with NFS. Antlers of deer fed with HFS or NFS showed in vitro neuronal protection of PC-12 cells against oxidative stress in a dose-dependent manner, where antler of deer fed with HFS generally had higher cellular viability than NFS. These results above suggest that the incorporation of the medicinal herbal complex into feedstuff may improve the biological effects of deer antlers.