• 대한안전경영과학회지
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• 제13권3호
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• pp.1-8
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• 2011

The overall goal of a safety based railroad system is either to eliminate hazards in designing or to minimize the possibility of it. In order to indicate system safety or low risk although it may not be possible to achieve zero risk conditions, first, it shall ensure that any disasters would occur due to system operation because the prescribed specifications are properly fulfilled and there are no failures of any kind. Second, the risk of faults or failures leading to a mishap must be eliminated or minimized by using fault-tolerance or fail-safe procedures. This paper will attempt to summarize the personal and social risk criterion at widely scattered points, presently used as a safety approach in all over EU, in order to establish the step by step procedures of the detailed standard for railway facilities. In addition, we present the new safety analysis method using the SIL-based evaluation standard and the Reachability Graph of the Petri Net.

• 대한조선학회논문집
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• 제60권2호
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• pp.86-94
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• 2023

Tonnage taxation has contributed to developing the Korean maritime industry through tax relief for shipping companies. The current tonnage taxation relies on the net tonnage as an earning-capacity indicator in a merchant ship. Although the tonnage tax accords with horizontal equity, it does not match vertical equity because of the different taxable capacities of an individual company. Nowadays, maritime transport uses a dedicated vessel, and each shipping freight embeds a different value of time. It means the tonnage taxation regime should consider the added value of each shipping freight. Meanwhile, as the environmental regulations led by the International Maritime Organization are being strengthened, the Korean merchant fleet must be eco-friendly soon after. This study explores the alternative to renewing tonnage taxation by utilizing the Greenship certification and considering the ability-to-pay principle. Because the Greenship certification scheme encourages shipping decarbonization, maritime transport by a certified ocean-going vessel comes to be treated as an activity for the green economy. Special taxation for the green economy may contribute to shipping sustainability and market competitiveness.

• Nuclear Engineering and Technology
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• 제49권1호
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• pp.1-5
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• 2017

The heavy water zero power reactor (HWZPR), which is a critical assembly with a maximum power of 100 W, can be used in different lattice pitches. The last change of core configuration was from a lattice pitch of 18-20 cm. Based on regulations, prior to the first operation of the reactor, a new core was simulated with MCNP (Monte Carlo N-Particle)-4C and WIMS (Winfrith Improved Multigroup Scheme)-CITATON codes. To investigate the criticality of this core, the effective multiplication factor ($K_{eff}$) versus heavy water level, and the critical water level were calculated. Then, for safety considerations, the reactivity worth of $D_2O$, the reactivity worth of safety and control rods, and temperature reactivity coefficients for the fuel and the moderator, were calculated. The results show that the relevant criteria in the safety analysis report were satisfied in the new core. Therefore, with the permission of the reactor safety committee, the first criticality operation was conducted, and important physical parameters were measured experimentally. The results were compared with the corresponding values in the original core.

• Nuclear Engineering and Technology
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• 제54권2호
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• pp.661-665
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• 2022

The 3 MeV proton irradiation effects on SiGe low noise amplifier (LNA) (NXP BGU7005) performance under different voltage supply VCC (0 V, 2.5 V) conditions were firstly experimental studied in this present work. The S parameters including S₁₁, S₂₂, S₂₁, 1 dB compression point and noise figure (NF) of the test samples under different bias voltage supply were measured and compared before and after 3 MeV proton irradiation. The total proton irradiation fluence was 1 × 10¹⁵ protons/cm². The maximum degradation quantities of the gain S₂₁ and NF of the test samples under zero bias are measured respectively 1.6 dB and 1.2 dB. Compared with the samples under 2.5 V bias supply, the maximum degradation of S₂₁ and NF are respectively 1.1 dB and 0.8 dB in the whole frequency band. It is noteworthy that the gain and NF of SiGe LNAs under zero-bias mode suffer enhanced degradation compared with those under normal bias supply. The key influence factors are discussed based on the correlation of the SiGe device and the LNA circuit. Different process of the ionization damage and displacement damage under zero-bias and 2.5 V bias voltage supply contributed to the degradation difference. The underlying physical mechanisms are analyzed and investigated.

• 한국산림과학회지
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• 제78권2호
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• pp.151-159
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• 1989

우리나라 온대림(溫帶林)에 분포(分布)하는 낙엽성(落葉性) 참나무류(類)의 생리(生理) 생태적(生態的) 습성(習性)을 밝히기 위하여 이번 연구에서는 신갈나무, 갈참나무, 굴참나무, 졸참나무 엽(葉)의 광합성속도(光合成速度)와 호흡속도(呼吸速度)에 미치는 광(光), 온도(溫度), 수분(水分)의 영향을 조사(調査) 하였다. 그 결과(結果)를 요약(要約)하면 다음과 같다. 1. 졸참나무, 신갈나무, 굴참나무, 갈참나무 엽(葉)의 광보상점(光補償點)은 각각 18, 20, 24, $38{\mu}Em^{-2}S^{-1}$ 였으며, 광포화점(光飽和點)은 갈참나무 엽(葉)을 제외한 3수종(樹種)에서 약 $500{\mu}Em^{-2}{\cdot}s^{-1}$였다. 2. 갈참나무, 신갈나무, 졸참나무, 굴참나무 엽(葉)의 최대(最大) 순광합성속도(純光合成速度)는 각각 11.0, 11.2, 15.2, 19.7 mg $CO_2dm^{-2}h^{-1}$였다. 3. 굴참나무와 졸참나무엽(葉)의 기공증산속도(氣孔蒸散速度)는 신갈나무와 갈참나무엽(葉)보다 높았으며 각피증산속도(角皮蒸散速度)는 4수종(樹種)모두 비슷하였다. 4. 최적광합성(最適光合成) 온도(溫度)는 신갈나무엽(葉)에서는 약$20^{\circ}C$, 갈참나무, 굴참나우, 졸참나무엽(葉)에서는 약$25^{\circ}C$ 였으며, 4수종(樹種)모두 약 $40^{\circ}C$에서 순광합성속도(純光合成速度)가 0에 달했다. 5. 엽(葉)의 암호흡속도(暗呼吸速度)의 크기는 굴참나무>신갈나무>갈참나무>졸참나무 순이였다. 6. 엽(葉)의 최대(最大) 생산효율(生産效率)(Pg/Rd)은 졸참나무와 신갈나무는 $20^{\circ}C$, 갈참나무는 $25^{\circ}C$, 굴참나무는 $15^{\circ}C$에서 일어났으며 그 크기는 졸참나무>신갈나무>갈참나무>굴참나무 순이였다. 7. 졸참나무엽(葉)의 순광합성속도(純光合成速度)는 -1.2Mpa에서 초기감소(初期減少)가 시작되어 2.9Mpa에서 0에 달했다. 또 엽(葉)이 3%의 수분손실(水分損失)을 받으면 순광합성속도(純光合成速度)의 초기감소(初期減少)가 시작되어 17.5%의 수분손실(水分損失)에서 0에 달했다. 8. p-v곡선(曲線)에 의해 얻은 수분특성인자(水分特性因子)로 판단(判斷)할때 갈참나무와 굴참나무가 신갈나무와 졸참나무 보다 내건성(耐乾性)이 더 강(强)함을 알 수 있었다.

• 대한안전경영과학회지
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• 제15권4호
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• pp.435-448
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• 2013

The aim of this study is to investigate and develop the extended models for Economic Cash Amount(ECA), Cash Break Even-Point(BEP), and Cash Flow Statement(CFS) by referencing systematic literature review in the field. The study develops three extended models to determine the optimal cash amount: ECA model with interest opportunity cost, financing transaction cost and financing fail cost, ECA model with daily cash supply and interest opportunity cost, ECA model with financing fail cost and interest opportunity cost. Earnings Before Interests, Tax, Depreciation and Amortization(EBITDA) is obtained by subtracting noncash depreciation costs from Earning Before Interest and Tax(EBIT), which is efficient metric to evaluate operating cash flow. The research also develops two extended Cash BEP models, considered as interest and corporate tax, in order to indentify the break-even point as EBITDA equals zero. Furthermore, this paper proposes the modified version of CFS by introducing the reclassification of operating and financing accounts in the statement of financial position. In addition, the study also present the reclassification of five types of profit, such as gross profit, EBIT, ordinary profit, special profit, and net profit within the statement of comprehensive income. In order to provide a better understanding of the proposed cash flow models, numerical examples, such as two-sample t test and Analysis of Variance(ANOVA), are presented to demonstrate the statistical significance according to the industrial types for net working capital(i.e cash-to-cash), net profit, operating cash flow and free cash flow.

• 한국자원식물학회지
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• 제8권2호
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• pp.195-199
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• 1995

대두(大豆) 수량(收量)이 우수한 은하(銀河), 방사(放射), 팔달(八達) 재배품종(栽培品種)을 광합성활성폭사선(光合成活性幅射線) ((PAR) 범위(範圍)에서 5본엽기(本葉期)($V_5$)에 엽온(葉溫)을 달리하여 광합성속도(光合成速度)와 호흡속도(呼吸速度)의 변화를 측정하였고, 품종별(品種別) 엽(葉)의 특성인 비엽중(比葉重)(SLW), 엽녹소함양(葉綠素含量)과 광합성(光合成)과의 관계를 조사한 결과(結果)는 다음과 같다. 1. $25^{\circ}C$에서 순광합성속도(純光合成速度)(Net Photosynthesis)는 은하(銀河) $21.5mgdm^{-2}h^{-1}$, 방사(放射) $20.2mgdm^{-2}h^h{-1}$, 팔달(八達) $18.5mgdm^{-2}h^{-1}$이었다. 2. 전품종(全品種) 모두 엽온(葉溫) $25^{\circ}C$에서 광합성속도(光合成速度)가 가장 높았고 은하(銀河) 품종(品種)이 우수(優秀)했으며, 엽형(葉型)은 은하(銀河) (Long) > 방사(放射)(Oval) > 팔달(八達)(Round) 순서였다. 3. 엽(葉)의 호흡연도(呼吸連度)는 은하(銀河), 방사(放射), 팔달(八達)에서 $15^{\circ}$ $0.56mgdm^{-2}h^{-1}$, $20^{\circ}C$ $0.79mgdm^{-2}h^{-1}$, $25^{\circ}$ $1,15mgdm^{-2}h^{-1}$, $30^{\circ}C$ $1.37mgdm^{-2}h^{-1}$였다. 4. 비엽중(比葉重)은 방사(放射)가 $3.1mg/cm^2$이었고, 은하(銀河)와 팔달(八達)은 $3.5mg/cm^2$이었으며 비엽중(比葉重)과 광합성(光合成)과는 유의성(有意性)이 인정되지 않았다. 5. 엽녹소(葉綠素) 함량(含量)은 은하(銀河)가 $2.48{\mu}g/gF.W.$으로 가장 높았고, 방사(放射)가 $2.19{\mu}g/gF.W.$이었고 팔달(八達)이 $1.67{\mu}g/gF.W.$로 가장 낮았으며 엽록소(葉綠素) 함량(含量)과 광합성(光合成)과는 유의성(有意性)이 인정되었다. 6. 광보상점(光補償點)은 $15^{\circ}C$에서는 $10{\mu}Em^{-2}s^{-1}$로 모두 같았으나, $20^{\circ}C$에서 은하(銀河)는 $12{\mu}Em^{-2}s^{-1}$이었고, 방사(放射)와 팔달(八達)은 $13{\mu}Em^{-2}s^{-1}$이었다. $25^{\circ}C$에서는 은하(銀河)와 방사(放射)가 $16{\mu}Em^{-2}s^{-1}$이었지만 팔달은 $18{\mu}$m^{-2}s^{-1}$이었고, $30^{\circ}C$에서는 은하(銀河)와 방사(放射)가 $22{\mu}Em^{-2}s^{-1}$이었지만, 팔달은 $23{\mu}Em^{-2}s^{-1}$이었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2753-2756
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• 2007

In the present study, we reduce the drag and lift fluctuations of the sphere by providing a linear proportional control. For this purpose, we measure the radial velocity along the centerline in the wake and provide blowing and suction at a part of sphere surface based on the measured velocity. Zero-net mass flow rate is satisfied during the control. This control is applied to the flow over a sphere at Re=300 and 425. We vary the sensing location at $0.8d{\leq}X_s{\leq}1.3d$ and find that the most effective sensing region coincides with the location at which minimum correlation between the lift and sensing-velocity directions occurs. As a result, the lift and drag fluctuations are significantly reduced.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.227-230
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• 2000

Batch cultivations of Anaerobiospirillum succiniciproducens have been systematically studied for the economical production of succinic acid from wood hydrolysate with corn steep liquor(CSL) as a nitrogen source. CSL was found to be an alternative complex nitrogen source for A. succiniciproducens when glucose and wood hydrolysate were used as carbon sources. Compared with polypeptone and/or yeast extract, CSL had similar effects on fermentation performance such as succinic acid yield and a ratio of succinic acid to acetic acid in the fermentation of wood hydrolysate as well as glucose. This means that succinic acid can be produced more economically from wood hydrolysate and CSL than relatively expensive carbon and nitrogen sources. Besides its low cost, the alternative medium served as a green technology for succinic acid production because it gives a net-zero effect on global warming.

• 한국광학회:학술대회논문집
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• 한국광학회 1990년도 제5회 파동 및 레이저 학술발표회 5th Conference on Waves and lasers 논문집 - 한국광학회
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• pp.115-120
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• 1990

The spectroscopic properties of Cr3+-doped sapphire and Ti3+-doped sapphire fibers are reported. Tensile stress produces blue shifts of the R lines and changes in their radiative lifetimes and integrated intensities which can be correlated to stress-induced changes of the crystal-field parameters in a Cr3+-doped sapphire fiber. A net red shift of the zero phonon fluorescence line of 2Eg state and a decrease of the splittings of 2T2g state with uniaxial stress are observed in a Ti3+-doped sapphire. In excitation spectra the two peaks from the 2Eg state are shifted to the blue with different rates. The changes are attributed to the stress-induced changes of crystal field and Jahn-Teller effect.