• Journal of applied mathematics & informatics
• /
• 제15권1_2호
• /
• pp.109-126
• /
• 2004

This paper deals with two problems of optimal portfolio strategies in continuous time. The first one studies the optimal behavior of a firm who is forced to withdraw funds continuously at a fixed rate per unit time. The second one considers a firm that is faced with an uncontrollable stochastic cash flow, or random risk process. We assume the firm's income can be obtained only from the investment in two assets: a risky asset (e.g., stock) and a riskless asset (e.g., bond). Therefore, the firm's wealth follows a stochastic process. When the wealth is lower than certain legal level, the firm goes bankrupt. Thus how to invest is the fundamental problem of the firm in order to avoid bankruptcy. Under the case of different lending and borrowing rates, we obtain the optimal portfolio strategies for some reasonable objective functions that are the piecewise linear functions of the firm's current wealth and present some interesting proofs for the conclusions. The optimal policies are easy to be operated for any relevant investor.

• Journal of Nutrition and Health
• /
• 제52권1호
• /
• pp.1-5
• /
• 2019

Purpose: This review describes the historical changes in nutrition philosophy from a reductionist to a holistic approach during the $20^{th}$ century. Also, the role and efficient use of a holistic approach to precision nutrition are discussed. Results: Over the past century, significant progress has been made in human nutrition research, unraveling fundamental mechanisms of single nutrients on single targets or pathways. This kind of a reductionist approach has helped to save populations from nutrient deficiency diseases and improve associated health outcomes in large parts of the world. However, a new set of nutrition problems, like obesity and diet-related chronic diseases, are growing each year worldwide, increasing the financial burden on the health care system. A linear cause-effect association between single nutrients and a single physiologic effect, is insufficient to solve the complex nutrition-health relationships. Research that involves a more holistic rather than reductionist approach is needed to tackle a new set of nutrition problems. Recent advances in technology, informatics, and statistical methods are enabling an understanding of the diversity of individuals and the complex interactions between foods and human bodies, leading to the concept of "precision nutrition." Conclusion: The emerging goal of precision nutrition is to provide tailored dietary advice for maintaining health and preventing obesity and diet-related chronic diseases. The parts are already being installed. To grab the complexity, reductionism and holism must be used interdependently.

• Genomics & Informatics
• /
• 제20권1호
• /
• pp.2.1-2.11
• /
• 2022

The method of single-cell RNA sequencing has been rapidly developed, and numerous experiments have been conducted over the past decade. Their results allow us to recognize various subpopulations and rare cell states in tissues, tumors, and immune systems that are previously unidentified, and guide us to understand fundamental biological processes that determine cell identity based on single-cell gene expression profiles. However, it is still challenging to understand the principle of comprehensive gene regulation that determines the cell fate only with transcriptome, a consequential output of the gene expression program. To elucidate the mechanisms related to the origin and maintenance of comprehensive single-cell transcriptome, we require a corresponding single-cell epigenome, which is a differentiated information of each cell with an identical genome. This review deals with the current development of single-cell epigenomic library construction methods, including multi-omics tools with crucial factors and additional requirements in the future focusing on DNA methylation, chromatin accessibility, and histone post-translational modifications. The study of cellular differentiation and the disease occurrence at a single-cell level has taken the first step with single-cell transcriptome and is now taking the next step with single-cell epigenome.

• 연구윤리
• /
• 제3권1호
• /
• pp.7-11
• /
• 2022

Purpose: The purpose of this study is to derive clues about the development direction of research ethics and areas of interest which has recently become a social issue in Korea by confirming overseas research trends. Research design, data and methodology: We collected 2,760 articles in scienceON, which including 'research ethics' in their paper. For analysis, frequency analysis, word clouding, keyword association analysis, and LDA topic modeling were used. Results: It was confirmed that many of the papers were published in medical, bio, pharmaceutical, and nursing journals and its interest has been continuously increasing. From word frequency analysis, many words of medical fields such as health, clinical, and patient was confirmed. From topic modeling, 7 topics were extracted such as ethical policy development and human clinical ethics. Conclusions: We founded that overseas research trends on research ethics are related to basic aspects than Korea. This means that a fundamental approach to ethics and the application of strict standards can become the basis for cultivating an overall ethical awareness. Therefore, academic discussions on the application of strict standards for publishing ethics and conducting researches in various fields where community awareness and social consensus are necessary for overall ethical awareness.

• 한국산학기술학회논문지
• /
• 제17권8호
• /
• pp.208-214
• /
• 2016

인공지능과 빅데이터 기술을 기반으로 하는 지능 정보 기술에 대한 관심이 높아지고 있고, 미국, 영국, 일본 등 주요 선진국을 비롯한 세계 각국은 소프트웨어 산업을 중심으로 하는 제4차 산업혁명에 대비하기 위한 국가적 투자를 아끼지 않고 있다. 우리나라도 뒤늦게나마 소프트웨어에 대한 중요성을 인식하고 초중등 정보교과를 위한 2015년 개정 교육과정을 고시 하였다. 본 논문에서는 고등학교 정보과학의 새로운 교육과정을 살피고, 정보윤리와 멀티미디어를 중심으로 개선방안에 대해 제시한다. 고등학교 정보과학은 우리나라 과학기술을 이끌어나갈 전국의 20여개 과학고 및 영재학교에서 주로 적용되어 지고 있다. 정보기술의 의존도가 더욱 커져갈 앞으로의 인공지능 시대에 그동안의 역기능 중심의 정보윤리 교육과는 다른, 인공지능 시스템을 만들고 주도적으로 활용해나갈 과학영재를 위한 정보윤리교육이 반드시 필요하다. 또한, 실생활에서 흔히 사용하는 이미지와 사운드, 동영상 등의 디지털원리와 압축 기술을 중심으로 하는 멀티미디어 교육은 교육과정에 추가될 필요가 있으며, 컴퓨터과학의 기본 개념과 원리, 기술을 바탕으로 실생활 및 다양한 학문 분야의 문제를 창의적이고 효율적으로 해결하는 능력을 키우고자하는 2015 개정 교육과정의 목표를 더 공고히 할 수 있을 것이다.

• 한국식품위생안전성학회지
• /
• 제38권5호
• /
• pp.402-408
• /
• 2023

국내 소비자들의 식품 영양성분에 대한 관심이 계속적으로 증가하고 있지만 영양성분과 관련된 식품의 소비자 선호도 분석 연구는 부족한 실정이다. 본 연구는 대국민 정보 서비스인 식품영양성분 데이터베이스 플랫폼에 수집된 빅데이터의 로그분석을 수행하여 소비자들이 영양학적 측면에서 관심을 가지는 식품에 대한 선호도 결과를 제시하였다. 수집 기간은 2020년 1월부터 2022년 12월까지의 3개년으로 설정하여 총 2,243,168건의 식품명 검색어가 수집되었으며, 식품명을 병합하여 품목대표 식품명으로 가공하였다. 분석도구는 R프로그램을 이용하였으며, 영양정보를 확인하고자 하는 식품명의 검색 빈도를 전체 기간 및 계절별로 분석하였다. 전체 기간 동안 빈도수 분석 결과, 한국인이 일반적으로 자주 섭취하는 쌀밥, 닭고기, 달걀의 빈도수가 가장 높았다. 계절성에 따른 선호도 분석 결과, 봄과 여름에는 대체적으로 국물이 없고 뜨겁지 않은 음식의 빈도수가 높았으며, 가을과 겨울에는 국물이 있고 따뜻한 음식의 빈도수가 높았다. 또한, 외식업체에서 계절식품으로 판매하는 냉면, 콩국수 등과 같은 식품의 빈도수도 계절성을 가지는 것으로 확인되었다. 이러한 결과는 소비자들이 일반적으로 자주 섭취하는 식품의 영양정보에 관심을 가지는 패턴을 확인할 수 있었으며, 소비 트렌드와 간접적인 연관성을 가진다는 점에서 외식업계에서 계절별 마케팅 전략 수립 시 기초 자료로 활용될 수 있을 것으로 기대된다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제29권1호
• /
• pp.36-42
• /
• 2016

Milk-related traits (milk yield, fat and protein) have been crucial to selection of Holstein. It is essential to find the current selection trends of Holstein. Despite this, uncovering the current trends of selection have been ignored in previous studies. We suggest a new formula to detect the current selection trends based on single nucleotide polymorphisms (SNP). This suggestion is based on the best linear unbiased prediction (BLUP) and the Fisher's fundamental theorem of natural selection both of which are trait-dependent. Fisher's theorem links the additive genetic variance to the selection coefficient. For Holstein milk production traits, we estimated the additive genetic variance using SNP effect from BLUP and selection coefficients based on genetic variance to search highly selective SNPs. Through these processes, we identified significantly selective SNPs. The number of genes containing highly selective SNPs with p-value <0.01 (nearly top 1% SNPs) in all traits and p-value <0.001 (nearly top 0.1%) in any traits was 14. They are phosphodiesterase 4B (PDE4B), serine/threonine kinase 40 (STK40), collagen, type XI, alpha 1 (COL11A1), ephrin-A1 (EFNA1), netrin 4 (NTN4), neuron specific gene family member 1 (NSG1), estrogen receptor 1 (ESR1), neurexin 3 (NRXN3), spectrin, beta, non-erythrocytic 1 (SPTBN1), ADP-ribosylation factor interacting protein 1 (ARFIP1), mutL homolog 1 (MLH1), transmembrane channel-like 7 (TMC7), carboxypeptidase X, member 2 (CPXM2) and ADAM metallopeptidase domain 12 (ADAM12). These genes may be important for future artificial selection trends. Also, we found that the SNP effect predicted from BLUP was the key factor to determine the expected current selection coefficient of SNP. Under Hardy-Weinberg equilibrium of SNP markers in current generation, the selection coefficient is equivalent to $2^*SNP$ effect.

• Earthquakes and Structures
• /
• 제5권2호
• /
• pp.161-205
• /
• 2013

We study seismically induced, anti-plane strain wave motion in a non-homogeneous geological region containing tunnels. Two different scenarios are considered: (a) The first models two tunnels in a finite geological region embedded within a laterally inhomogeneous, layered geological profile containing a seismic source. For this case, labelled as the first boundary-value problem (BVP 1), an efficient hybrid technique comprising the finite difference method (FDM) and the boundary element method (BEM) is developed and applied. Since the later method is based on the frequency-dependent fundamental solution of elastodynamics, the hybrid technique is defined in the frequency domain. Then, an inverse fast Fourier transformation (FFT) is used to recover time histories; (b) The second models a finite region with two tunnels, is embedded in a homogeneous half-plane, and is subjected to incident, time-harmonic SH-waves. This case, labelled as the second boundary-value problem (BVP 2), considers complex soil properties such as anisotropy, continuous inhomogeneity and poroelasticity. The computational approach is now the BEM alone, since solution of the surrounding half plane by the FDM is unnecessary. In sum, the hybrid FDM-BEM technique is able to quantify dependence of the signals that develop at the free surface to the following key parameters: seismic source properties and heterogeneous structure of the wave path (the FDM component) and near-surface geological deposits containing discontinuities in the form of tunnels (the BEM component). Finally, the hybrid technique is used for evaluating the seismic wave field that develops within a key geological cross-section of the Metro construction project in Thessaloniki, Greece, which includes the important Roman-era historical monument of Rotunda dating from the 3rd century A.D.

• Genomics & Informatics
• /
• 제15권1호
• /
• pp.19-27
• /
• 2017

Understanding complex relationships among heterogeneous biological data is one of the fundamental goals in biology. In most cases, diverse biological data are stored in relational databases, such as MySQL and Oracle, which store data in multiple tables and then infer relationships by multiple-join statements. Recently, a new type of database, called the graph-based database, was developed to natively represent various kinds of complex relationships, and it is widely used among computer science communities and IT industries. Here, we demonstrate the feasibility of using a graph-based database for complex biological relationships by comparing the performance between MySQL and Neo4j, one of the most widely used graph databases. We collected various biological data (protein-protein interaction, drug-target, gene-disease, etc.) from several existing sources, removed duplicate and redundant data, and finally constructed a graph database containing 114,550 nodes and 82,674,321 relationships. When we tested the query execution performance of MySQL versus Neo4j, we found that Neo4j outperformed MySQL in all cases. While Neo4j exhibited a very fast response for various queries, MySQL exhibited latent or unfinished responses for complex queries with multiple-join statements. These results show that using graph-based databases, such as Neo4j, is an efficient way to store complex biological relationships. Moreover, querying a graph database in diverse ways has the potential to reveal novel relationships among heterogeneous biological data.

• Genomics & Informatics
• /
• 제10권3호
• /
• pp.194-199
• /
• 2012

In addition to single-nucleotide polymorphisms (SNP), copy number variation (CNV) is a major component of human genetic diversity. Among many whole-genome analysis platforms, SNP arrays have been commonly used for genomewide CNV discovery. Recently, a number of CNV defining algorithms from SNP genotyping data have been developed; however, due to the fundamental limitation of SNP genotyping data for the measurement of signal intensity, there are still concerns regarding the possibility of false discovery or low sensitivity for detecting CNVs. In this study, we aimed to verify the effect of combining multiple CNV calling algorithms and set up the most reliable pipeline for CNV calling with Affymetrix Genomewide SNP 5.0 data. For this purpose, we selected the 3 most commonly used algorithms for CNV segmentation from SNP genotyping data, PennCNV, QuantiSNP; and BirdSuite. After defining the CNV loci using the 3 different algorithms, we assessed how many of them overlapped with each other, and we also validated the CNVs by genomic quantitative PCR. Through this analysis, we proposed that for reliable CNV-based genomewide association study using SNP array data, CNV calls must be performed with at least 3 different algorithms and that the CNVs consistently called from more than 2 algorithms must be used for association analysis, because they are more reliable than the CNVs called from a single algorithm. Our result will be helpful to set up the CNV analysis protocols for Affymetrix Genomewide SNP 5.0 genotyping data.