• Korean Management Science Review
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• v.27 no.2
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• pp.21-29
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• 2010

We consider an economic approach for spectrum operations in mobile networks. We present the investment function of base stations according to the number of FAs assuming the linearity of cell splitting. We show that there is an economic amount of spectrum which corresponds to the optimal number of FAs that minimizes the investment. We analyze the impact of the cost structure and the traffic distribution in base stations on the economic amount of spectrum. This paper is applicable to an economic spectrum operation for mobile operators. In addition, the national regulatory authority can use the economic amount of spectrum as the minimal amount for spectrum allocation.

• Journal of information and communication convergence engineering
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• v.9 no.2
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• pp.166-171
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• 2011

This paper investigates the design issues of spectrum sensing in the cognitive radio (CR) networks of opportunistic unlicensed spectrum access. The cognitive radios can perform a communication using the incumbent user spectrum band without the interference caused by the cognitive radio users. In this case, the cognitive radios must know the real-time radio environments of the incumbent user spectrum band using the spectrum sensing, beacon signal, and geo-location database access. Then in this paper, we are going to provide spectrum sensing issues which include the sensing techniques, the regulatory requirements, the analysis of DTV detection threshold, and main considerations associated with the spectrum sensing design in cognitive radio systems. Also, this paper introduces design trade-offs in order to optimize the sensing parameters such as sensing time and sensing complexity.

• Molecules and Cells
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• v.39 no.5
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• pp.395-402
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• 2016

Identifying Hoxc8 target genes is at the crux of understanding the Hoxc8-mediated regulatory networks underlying its roles during development. However, identification of these genes remains difficult due to intrinsic factors of Hoxc8, such as low DNA binding specificity, context-dependent regulation, and unknown cofactors. Therefore, as an alternative, the present study attempted to test whether the roles of Hoxc8 could be inferred by simply analyzing genes frequently coexpressed with Hoxc8, and whether these genes include putative target genes. Using archived gene expression datasets in which Hoxc8 was differentially expressed, we identified a total of 567 genes that were positively coexpressed with Hoxc8 in at least four out of eight datasets. Among these, 23 genes were coexpressed in six datasets. Gene sets associated with extracellular matrix and cell adhesion were most significantly enriched, followed by gene sets for skeletal system development, morphogenesis, cell motility, and transcriptional regulation. In particular, transcriptional regulators, including paralogs of Hoxc8, known Hox co-factors, and transcriptional remodeling factors were enriched. We randomly selected Adam19, Ptpn13, Prkd1, Tgfbi, and Aldh1a3, and validated their coexpression in mouse embryonic tissues and cell lines following $TGF-{\beta}2$ treatment or ectopic Hoxc8 expression. Except for Aldh1a3, all genes showed concordant expression with that of Hoxc8, suggesting that the coexpressed genes might include direct or indirect target genes. Collectively, we suggest that the coexpressed genes provide a resource for constructing Hoxc8-mediated regulatory networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2A
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• pp.174-180
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• 2004

The World Radiocommunication Conference in year of 2000 adopted new Plans as well as Lists for BSS and its feeder-link in the Regions 1 and 3, based on the new technical criteria such as small size of antenna and low satellite power. Since the new Plans and Lists were based on new technical criteria, ITU was requested to review the relevant regulatory procedures and sharing criteria of broadcasting satellite networks contained in Appendices 30 and 30A of Radio Regulations. Korean BSS network at 116$^{\circ}$E was chosen for the study and ITU S/W (MSPACEG) was used. We analyzed the interference effects from adjacent BSS networks to Korean BSS network using parameters of an antenna diameter and polarization of receiving earth station. The analysis shows that it is difficult to co-operate BSS networks both at 116$^{\circ}$E and 113$^{\circ}$E, however, it is possible to use small antenna (i.e. 45cm) in frequency sharing among BSS networks with 6$^{\circ}$ orbital separation.

• IMMUNE NETWORK
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• v.11 no.5
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• pp.227-244
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• 2011

MicroRNAs (miRNAs) are small noncoding RNA molecules that negatively regulate gene expression via degradation or translational repression of their target messenger RNAs (mRNAs). Recent studies have clearly demonstrated that miRNAs play critical roles in several biologic processes, including cell cycle, differentiation, cell development, cell growth, and apoptosis and that miRNAs are highly expressed in regulatory T (Treg) cells and a wide range of miRNAs are involved in the regulation of immunity and in the prevention of autoimmunity. It has been increasingly reported that miRNAs are associated with various human diseases like autoimmune disease, skin disease, neurological disease and psychiatric disease. Recently, the identification of miRNAs in skin has added a new dimension in the regulatory network and attracted significant interest in this novel layer of gene regulation. Although miRNA research in the field of dermatology is still relatively new, miRNAs have been the subject of much dermatological interest in skin morphogenesis and in regulating angiogenesis. In addition, miRNAs are moving rapidly center stage as key regulators of neuronal development and function in addition to important contributions to neurodegenerative disorder. Moreover, there is now compelling evidence that dysregulation of miRNA networks is implicated in the development and onset of human neruodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, Tourette's syndrome, Down syndrome, depression and schizophrenia. In this review, I briefly summarize the current studies about the roles of miRNAs in various autoimmune diseases, skin diseases, psychoneurological disorders and mental stress.

• BMB Reports
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• v.37 no.1
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• pp.83-92
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• 2004

As a result of the enormous amount of information that has been collected with E. coli over the past half century (e.g. genome sequence, mutant phenotypes, metabolic and regulatory networks, etc.), we now have detailed knowledge about gene regulation, protein activity, several hundred enzyme reactions, metabolic pathways, macromolecular machines, and regulatory interactions for this model organism. However, understanding how all these processes interact to form a living cell will require further characterization, quantification, data integration, and mathematical modeling, systems biology. No organism can rival E. coli with respect to the amount of available basic information and experimental tractability for the technologies needed for this undertaking. A focused, systematic effort to understand the E. coli cell will accelerate the development of new post-genomic technologies, including both experimental and computational tools. It will also lead to new technologies that will be applicable to other organisms, from microbes to plants, animals, and humans. E. coli is not only the best studied free-living model organism, but is also an extensively used microbe for industrial applications, especially for the production of small molecules of interest. It is an excellent representative of Gram-negative commensal bacteria. E. coli may represent a perfect model organism for systems biology that is aimed at elucidating both its free-living and commensal life-styles, which should open the door to whole-cell modeling and simulation.

• Journal of Microbiology and Biotechnology
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• v.16 no.6
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• pp.832-848
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• 2006

Systems biology has recently become an important research paradigm that is anticipated to decipher the metabolic, regulatory, and signaling networks of complex living organisms on the whole organism level. Thus, various research outputs are being generated, along with the development of many tools and resources for systems biology research. Accordingly, this review provides a comprehensive summary of the current resources and tools for systems biology research that will hopefully be helpful to researchers involved in this field. The resources are categorized into the following five groups: genome information and analysis, transcriptome and proteome databases, metabolic profiling and metabolic control analysis, metabolic and regulatory information, and software for computational systems biology. A summary table and some future perspectives are also provided.

• Journal of the Korean Data and Information Science Society
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• v.27 no.1
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• pp.225-243
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• 2016

Thanks to recent advance of next generation sequencing techniques, RNA-seq enabled to have an unprecedented opportunity to identify transcript variants with isoform diversity and allelic imbalance (Anders et al., 2012) by different transcriptional rates. To date, it is well known that those features might be associated with the aberrant patterns of disease complexity such as tissue (Anders and Huber, 2010; Anders et al., 2012; Nariai et al., 2014) specific differential expression at isoform levels or tissue specific allelic imbalance in mal-functionality of disease processes, etc. Nevertheless, the knowledge of post-transcriptional modification and AI in transcriptomic and genomic areas has been little known in the traditional platforms due to the limitation of technology and insufficient resolution. We here stress the potential of isoform variability and allelic specific expression that are relevant to the abnormality of disease mechanisms in transcriptional genetic regulatory networks. In addition, we systematically review how robust Bayesian approaches in RNA-seq have been developed and utilized in this regard in the field.

• Molecules and Cells
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• v.42 no.2
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• pp.166-174
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• 2019

Bacterial species in the genus Xanthomonas infect virtually all crop plants. Although many genes involved in Xanthomonas virulence have been identified through molecular and cellular studies, the elucidation of virulence-associated regulatory circuits is still far from complete. Functional gene networks have proven useful in generating hypotheses for genetic factors of biological processes in various species. Here, we present a genome-scale co-functional network of Xanthomonas oryze pv. oryzae (Xoo) genes, XooNet (www.inetbio.org/xoonet/), constructed by integrating heterogeneous types of genomics data derived from Xoo and other bacterial species. XooNet contains 106,000 functional links, which cover approximately 83% of the coding genome. XooNet is highly predictive for diverse biological processes in Xoo and can accurately reconstruct cellular pathways regulated by two-component signaling transduction systems (TCS). XooNet will be a useful in silico research platform for genetic dissection of virulence pathways in Xoo.

• Genomics & Informatics
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• v.20 no.1
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• pp.7.1-7.13
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• 2022

2-Methoxy-1,4-naphthoquinone (MNQ) has been shown to cause cytotoxic towards various cancer cell lines. This study is designed to investigate the regulatory effect of MNQ on the key cancer genes in mitogen-activated protein kinase, phosphoinositide 3-kinase, and nuclear factor κB signaling pathways. The expression levels of the genes were compared at different time point using polymerase chain reaction arrays and Ingenuity Pathway Analysis was performed to identify gene networks that are most significant to key cancer genes. A total of 43 differentially expressed genes were identified with 21 up-regulated and 22 down-regulated genes. Up-regulated genes were involved in apoptosis, cell cycle and act as tumor suppressor while down-regulated genes were involved in anti-apoptosis, angiogenesis, cell cycle and act as transcription factor as well as proto-oncogenes. MNQ exhibited multiple regulatory effects on the cancer key genes that targeting at cell proliferation, cell differentiation, cell transformation, apoptosis, reduce inflammatory responses, inhibits angiogenesis and metastasis.