• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• v.9 no.1
• /
• pp.79-90
• /
• 2005

In this paper we study the numerical solutions of the stochastic differential equations of the form $$du(x,\;t)=f(x,\;t,\;u)dt\;+\;g(x,\;t,\;u)dW(t)\;+\;\sum\limits_{|q|\leq2m}\;A_q(x,\;t)D^qu(x,\;t)dt$$ where $0\;{\leq}\;t\;{\leq}\;T,\;x\;{\in}\;R^{\nu}$, ($R^{nu}$ is the $\nu$-dimensional Euclidean space). Here $u\;{\in}\;R^n$, W(t) is an n-dimensional Brownian motion, $$f\;:\;R^{n+\nu+1}\;{\rightarrow}\;R^n,\;g\;:\;R^{n+\nu+1}\;{\rightarrow}\;R^{n{\times}n},$$, and $$A_q\;:\;R^{\nu}\;{\times}\;[0,\;T]\;{\rightarrow}\;R^{n{\times}n}$$ where ($A_q,\;|\;q\;|{\leq}\;2m$) is a family of square matrices whose elements are sufficiently smooth functions on $R^{\nu}\;{\times}\;[0,\;T]\;and\;D^q\;=\;D^{q_1}_1_{\ldots}_{\ldots}D^{q_{\nu}}_{\nu},\;D_i\;=\;{\frac{\partial}{\partial_{x_i}}}$.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.10 no.4
• /
• pp.227-235
• /
• 1977

The noise pressure scattered underwater on account of the engine revolution of a pole and liner, Kwan-Ak-San(G. T. 234.96), was measured at the locations of Lat. $34^{\circ}47'N$, Long. $128^{\circ}53'E$ on the 16th of August 1976 and Lat. $34^{\circ}27'N$, Long. $128^{\circ}23'E$ on the 28th of July, 1977. The noise pressure passed through each observation point (Nos. 1 to 5), which was established at every 10m distance at circumference of outside hull was recorded when the vessel was cruising and drifted. In case of drifting, the revolution of engine was fixed at 600 r. p. m. and the noise was recorded at every 10 m distance apart from observation point No. 3 in both horizontal and vertical directions with $90^{\circ}$ toward the stern-bow line. In case of cruising, the engine was kept in a full speed at 700 r.p.m. and the sounds passed through underwater in 1 m depth were also recorded while the vessel moved back and forth. The noise pressure was analyzed with sound level meter (Bruel & Kjar 2205, measuring range 37-140 dB) at the anechoic chamber in the Institute of Marine Science, National Fisheries University of Busan. The frequency and sound waves of the noise were analyzed in the Laboratory of Navigation Instrument. From the results, the noise pressure was closely related to the engine revolution shelving that the noise pressure marked 100 dB when .400 r. p. m. and increase of 100 r. p. m. resulted in 1 dB increase in noise pressure and the maximum appeared at 600 r. p. m. (Fig.5). When the engine revolution was fixed at 700 r. p. m., the noise pressures passed through each observation point (Nos. 1 to 5) placed at circumference of out side hull were 75,78,76,74 and 68 dB, the highest at No.2, in case of keeping under way while 75,76,77,70 and 67 dB, the highest at No.3 in case of drifting respectively (Fig.5). When the vessel plyed 1,400 m distance at 700 r.p.m., the noise pressure were 67 dB at the point 0 m, 64 dB at 600m and 56 dB at 1,400m on forward while 72 at 0 m, 66 at 600 m and 57 dB at 1,400 m on backward respectively indicating the Doppler effects 5 dB at 0 m and 3 dB at 200 m(Fig.6). The noise pressures passed through the points apart 1,10,20,30,40 and 50 m depth underwater from the observation point No.7 (horizontal distance 20 m from the point No.3) were 68,75,62,59,55 and 51 dB respectively as the vessel was being drifted maintaining the engine revolution at 600 r. p. m. (Fig. 8-B) whereas the noise pressures at the observation points Nos.6,7,8,9 and 10 of 10 m depth underwater were 64,75,55,58,58 and 52 dB respectively(Fig.8-A).

• Journal of Technology Innovation
• /
• v.10 no.1
• /
• pp.98-123
• /
• 2002

This study develops a Korean R&D Scoreboard which has originated from the R&D Scoreboard in United Kingdom. The Scoreboard contains details of the R&D investment, sales, growth, profits and employee numbers for Korean companies which are extracted from company annual reports and key ratios calculated, with some movements over time. Companies are classified by the Korea Standard Industrial Classification. The Scoreboard contains 190 companies which consist of 100 largest companies and 30 middle-or small-sized firms listed in Korea Stock Exchange (KSE), and 30 ventures and 30 other firms listed in KOSDAQ. The overall company R&D intensity (R&D as a percentage of sales) is 2.1% compared to the international average of 4.2%. Korea has an unusually large R&D percentage of sales in IT hardware (4.9%) and telecommunication (3.7%). R&D intensity is positively correlated with company performance measures such as profitability, sales growth, productivity and market value. For largest companies listed in KSE and ventures listed in KOSDAQ, the ratio of operating profit to sales is greater for high R&D intensity companies. Sales growth is in proportion to R&D intensity for all companies. Plots of value added per employee or sales per employee vs R&D per employee rise together for the sectors studied, especially for the chemical sectors and automobile sectors, demonstrating a correlation with productivity. The average market value of high R&D companies in the KSE has risen more than 1.6 times that of the KOSPI 200 index. Given the correlation between R&D intensity and company performance and given that R&D is a smaller percentage of surplus (profits plus R&D) than international level (both overall and in several sectors), the challenges facing Korean companies are to maintain the leading position in IT hardware and telecommunication, and to increase the intensity of R&D in many medium-intensive R&D sectors where Korea has an average intensity well below international or US levels.

• Journal of Technology Innovation
• /
• v.23 no.1
• /
• pp.87-105
• /
• 2015

This research confirms a non-linear relationship between R&D investment and performance of small and medium-sized enterprises and measures the adequate level as threshold value. Although previous studies did not consider the time lag and estimated indirectly the level using the R&D investment squared term, this study assumes 2 years time lag and uses the threshold estimation model to measure directly. We find that there is the S-curve relationship between the profit rate as R&D output and R&D intensity and the ratio of researchers to employees as R&D input. Also, we estimate the adequate levels of R&D investment, 6.4% for R&D intensity and 13% for the ratio of researchers to employees. This relationship and measurement of the level can offer basic facts and implications about R&D policy and strategy.

• Journal of Korea Technology Innovation Society
• /
• v.19 no.2
• /
• pp.302-323
• /
• 2016

To date, the literature has focused on formal R&D activities, such as internal, joint or external R&D, but informal R&D activities, such as job training or design, can also have a positive impact on technological innovation. To address this research gap, this paper examined 1) the influence of informal R&D activities on innovation adoption, and 2) the differences between formal R&D-oriented and informal R&D-oriented firms in process and product innovation. For this, statistical analysis was conducted using the data set from 2012 Korea Innovation Survey. The results suggest that 1) informal R&D activities can influence process innovation, and 2) firms engaging in both informal and formal R&D actively adopt product innovation. Findings suggest that 1) firms should recognize the importance of informal R&D and 2) national R&D policy should reflect the positive role of informal R&D in technological innovation.

• Proceedings of the Korean Society for Information Management Conference
• /
• 2017.08a
• /
• pp.99-99
• /
• 2017

최근 4차 산업혁명 시대 도래에 따른 빅데이터가 이슈화 되고 정부의 공공 데이터 개방? 공유 정책 등으로 정부의 R&D 정보화 서비스도 다양화되고 있다. 특히 해양수산 R&D사업은 해양이라는 공간적 제약으로 선박 및 특수 장비 등을 사용함에 따라 연구비 단가가 상대적으로 높은 실정임에도 해양수산 연구 자료 및 관측자료가 통합적으로 관리되지 않고, 사업별 기관별로 산발적으로 관리되고 있어, 이에 따라 연구 DB 통합관리의 수요가 제기 되고 있다. 이에 해양수산 R&D사업에서는 사업별 통합 DB 구축사업이 진행되고 있고, '관할해역해양정보 공동활용시스템(JOISS)'이 대표적이라 할 수 있다. JOISS는 2012년부터 시작된 '관할해역 해양정보 공동활용체계 구축'과제를 통해 자료 표준화 연구와 함께 해양과학조사 분야의 R&D과제들과 실시간 해양관측망으로부터 산출되는 데이터를 수집하고, 정보서비스를 구현한 시스템이다. 2016년 1차 시스템 구축을 완료하여 현재 서비스를 진행하고 있다. 한편, 해양관측 데이터 수집 공유 서비스 외 해양수산 R&D사업과 연계된 다양한 정보들을 나누고 소통하는 온라인 장을 구현하기 위해 '해양수산 R&D 지식정보 시스템(OFRIS)' 개발사업이 별도로 진행되고 있다. OFRIS는 해양수산 R&D사업을 통한 데이터의 원할한 수집 및 품질관리 등의 문제를 보완하고, 그 외에도 사업별로 분산 관리되고 있는 R&D 관련 정보를 연계하고, 기술공급자와 수요자를 직접 연결해 주는 '개방형 기술 정보 중개 시스템'으로의 역할, 국내외 해양수산 R&D관련 정책 연구 산업 동향을 엄선하여 제공하는 등 해양수산 R&D 종합 포털로서 기능구현을 목표하고 있다. 2017년 말 1단계 개발 완료를 앞두고 있으며, 1단계에서는 시급성 높고, 수요가 많은 (1) R&D동향, (2) 과제이력, (3) 연구성과, (4) 기술거래, (5) DB공유 등 5대 기능을 우선 구현하고, 2단계에서는 통계자료 생산 및 분석 기능 강화, 3단계에서는 해양수산 산업통계, 인력, 교육 등의 정보를 서비스하는 포털로 확장할 계획이다. JOISS, OFRIS를 개발하는 과정에서는 해양수산 R&D의 정보를 수집 관리 하는데 있어 다양한 현안 문제 등이 도출되었으며, 그 중에서도 연구자들의 자발적 데이터 제공 협조, 데이터의 표준화 및 품질검증, 구축된 데이터의 활용 및 피드백 등에 대해 구체적이고 현실적인 대응 방안이 요구된다.

• Journal of Korean Institute of Industrial Engineers
• /
• v.40 no.1
• /
• pp.84-99
• /
• 2014

In this study, determinant input-output variables are identified for calculating Data Envelopment Analysis (DEA) efficiency scores relating to evaluating the efficiency of government-sponsored research and development (R&D) projects. In particular, this study proposes a systematic framework of design and analysis of experiments, called "all possible DEAs", for pinpointing DEA determinant input-output variables. In addition to correlation analyses, two modified measures of time series analysis are developed in order to check the similarities between a DEA complete data structure (CDS) versus the rest of incomplete data structures (IDSs). In this empirical analysis, a few DEA determinant input-output variables are found to be associated with a typical public R&D performance evaluation logic model, especially oriented to a mid- and long-term performance perspective. Among four variables, only two determinants are identified : "R&D manpower" ($x_2$) and "Sales revenue" ($y_1$). However, it should be pointed out that the input variable "R&D funds" ($x_1$) is insignificant for calculating DEA efficiency score even if it is a critical input for measuring efficiency of a government-sonsored R&D project from a practical point of view a priori. In this context, if practitioners' top priority is to see the efficiency between "R&D funds" ($x_1$) and "Sales revenue" ($y_1$), the DEA efficiency score cannot properly meet their expectations. Therefore, meticulous attention is required when using the DEA application for public R&D performance evaluation, considering that discrepancies can occur between practitioners' expectations and DEA efficiency scores.

• Journal of Bio-Environment Control
• /
• v.14 no.4
• /
• pp.269-274
• /
• 2005

The purpose of this experiment was to investigate optimal ionic concentration of nutrient solution for water culture of young welsh onion (Allium fistulosum). For the purpose of clarification of optimal nutrient concentration to maximize growth of young welsh onion, different nutrient concentrations of Yamazaki's solution for welsh onion seedling $(NO_3^--N\;9.0,\;NH_4^+-N\;3.0,\;PO_4^{3-}-P\;6.0,\;K^+7.0,\;Ca^{2+}\;2.0,\;Mg^{2+}\;2.0,\;and\;SO_4^{2-}-S\;4.4me{\cdot}L^{-1})$ which selected by prior experiment were treated as 0.6, 1.2, 1.8, and $2.4dS{\cdot}m^{-1}$. Increments of fresh weight, dry weight and top length were the highest in 1.2 and, in the next, were placed by the order of 1.8, 2.4, and $0.6dS{\cdot}m^{-1}$ The regression coefficients for the maximal growth of fresh weight of cv. 'Geurnjanguedaepa' and 'Tokyokuro' were $y=-42.091x^2+171.79x+11.047 (R^2=0.8946,\; R=0.9458^*)\;and\;y=-50.069x2+157.58x+15.414(R^2=0.9343,\;R=0.9692^{**})$, respectively, and optimal EC levels according to regression coefficients were 1.68 and $1.57dS{\cdot}m^{-1}$. As the conclusions, optimal nutrient levels far young welsh onion were $1.2dS{\cdot}m^{-1}$ EC in the early growth stage and $1.6\~l .7dS{\cdot}m^{-1}$ in the later growth stage.

• Archives of Pharmacal Research
• /
• v.27 no.2
• /
• pp.177-183
• /
• 2004

In order to develop new anti-photoaging agents, we examined the antioxidative activity and the inhibition effect of matrix metalloproteinase-1 (MMP-1) on the extracts of a marine product, Zostera marina L., which is known for its potent activity. Three compounds (compounds 1, 2, and 3) were isolated from an ethyl acetate (EtOAc) soluble fraction of the product; they were identified as apigenin-7 -O-$\beta$-D-glucoside (1), chrysoeriol (2), and luteolin (3). These compounds were found to scavenge radicals and reactive oxygen species (ROS) and were measured to have $SC_{50}$/ values of 0.18 mM, 0.68 mM, and 0.01 mM against the 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical and 0.04 mM, 0.03 mM, and 0.01 mM against the superoxide radical in the xanthine/xanthine oxidase system, respectively. Compound 3 suppressed the expression of MMP-1 by up to 44％ at 4.0 $\mu$M and inhibited the production of interleukin 6 (IL-6), which is known as a cytokine that induces MMP-1 expression. From these results, compound 3 and the other compounds were determined to have antioxidative activity and to inhibit MMP-1 expression. Thus, the three compounds are expected to be useful for preventing the photoaging of skin.

• Bulletin of the Korean Mathematical Society
• /
• v.57 no.2
• /
• pp.407-417
• /
• 2020

Let (R, m) be a d-dimensional Cohen-Macaulay local ring with infinite residue field. Let I be an ideal of R that has analytic spread ℓ(I) = d, satisfies the G_d condition, the weak Artin-Nagata property AN^-_d-2 and m is not an associated prime of R/I. In this paper, we show that if j₁(I) = λ(I/J) + λ[R/(J_d-1 :_RI+(J_d-2 :_RI+I):_R m^∞)] + 1, then I has almost minimal j-multiplicity, G(I) is Cohen-Macaulay and r_J(I) is at most 2, where J = (x₁, _…, x_d) is a general minimal reduction of I and J_i = (x₁, _…, x_i). In addition, the last theorem is in the spirit of a result of Sally who has studied the depth of associated graded rings and minimal reductions for m-primary ideals.