• Title/Summary/Keyword: Depth control performance

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Analysis of the Spillover Effects on the Management Profits of Offshore Fishery by the Fluctuations in the Crude Oil Prices (원유가상승이 근해어업의 경영수지에 미치는 파급효과 분석)

  • 김현용;강연실
    • The Journal of Fisheries Business Administration
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    • v.32 no.1
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    • pp.15-39
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    • 2001
  • The study, using the input-output analysis of 402 industrial sectors by Bank of Korea(BOK) and the resulting outcomes of price model, aims to evaluate the spillover effects the international fluctuations in crude oil prices have on the commodities prices and consequently, analyse the management and profitability of the offshore fisheries in Korea. At present, the fisher men are provided with tax-free oils for their fishing operations as specified under the Special Tax Treatment Control Law. However, the exhaustion of marine resources and new international fisheries agreements, which resulted in the loss of fishing grounds, made the stable catch even more unpredictable and the hike in the price of the international crude oil would have adverse effects on the fishing industry. The study revealed that the increasing rise in the price of crude oil would exert sweeping spillover effects on other industry sectors in general and accordingly, lead to a poorer performance by fisheries. The price spillover coefficients for the diesel oil was 0.6026, which would translate into the 42.6% increase in the prices of oil when the increase ratio of 73.3% for the base crude oil was applied based on the calculation methods employed in the study. This in turn increased the ratio of diesel oil required in the offshore fisheries from 23.3% to 16.6%, diminishing the ratio of current net profits to minus 2.0% from 4.2% otherwise. By fishing type, the Pair Trawl suffered current net profits loss most by ratio of minus 9.4% and other fisheries such as Coastal Stow Nets, Coastal Angling, Danish Sein also suffered ratio of 7% and more in the loss of current net profits. With the deteriorating fishing performance, coupled with the increasing international crude oil prices, it is urgently required that the authorities concerned deliberate in depth on such schemes as follows in efforts to secure stable fishing production. First, provision of large-scale storage facilities for oil is needed to timely adapt to the fluctuations in international crude oil prices. Secondly, in line with the stabilization of tax-free oil prices, duty levied on oils for fishing and tax collected from the refineries need to be tax-exempt. Thirdly, the beneficiaries from the provision of tax-free oil should be broadened, not limited to special fishing operation only. Fourth, investment in stabilization of the oil prices should be encouraged, possibly through funding from the formation of fisheries development funds underway.

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Development of Integrated Type Main Frame and Downhole Sonde Apparatus for Hydraulic Packer Testing in Seabed Rock under High Water Pressure (고수압 해저지반 수리특성 조사용 일체형 메인 프레임과 공내 측정장치 개발)

  • Bae, SeongHo;Kim, Jangsoon;Jeon, Seokwon;Kim, Hagsoo
    • Tunnel and Underground Space
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    • v.28 no.3
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    • pp.258-276
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    • 2018
  • The accurate and quantitative ground information on the hydraulic conductivity characteristics of rock mass is one of the key factors for evaluation of the hydro-geological behaviour of rock mass around an excavated opening under high water pressure. For tunnel and rock structures in seabed, where the sea acts as an infinite source of water, its importance become greater with increasing construction depth below sea level. In this study, to improve the problems related with poor system configuration and incorrect data acquisition of previous hydraulic packer testing equipment, we newly developed an integrated main frame and 30 bar level waterproof downhole sonde apparatus, which were optimized for deep hydraulic packer test in seabed rock mass. Integration of individual test equipment into one frame allows safe and efficient field testing work on a narrow offshore drilling platform. For the integrated type main frame, it is possible to make precise stepwise control of downhole net injection pressure at intervals of $2.0kg_f/cm^2$ or less with dual hydraulic oil volume controller. To ensure the system performance and the operational stability of the prototype mainframe and downhole sonde apparatus, the field feasibility tests were completed in two research boreholes, and using the developed apparatus, the REV(Representative Elementary Volume) scale deep hydraulic packer tests were successfully carried out at a borehole located in the basalt region, Jeju. In this paper, the characteristics of the new testing apparatus are briefly introduced and also some results from the laboratory and in-situ performance tests are shown.

The Effect of Plant Coverage on the Constructed Wetlands Performance and Development and Management of Macrophyte Communities (식생피도가 인공습지의 질소 및 인 처리효율에 미치는 영향과 습지식물의 조성 및 관리)

  • Ham, Jong-Hwa;Kim, Hyung-Chul;Koo, Won-Seok;Shin, Hyun-Bhum;Yun, Chun-Gyeong
    • Korean Journal of Ecology and Environment
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    • v.38 no.3 s.113
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    • pp.393-402
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    • 2005
  • The field scale experiment was performed to examine the effect of plant coverage on the constructed wetland performance and recommend the optimum development and management of macrophyte communities. Four sets (each set of 0.88 ha) of wetland (0.8 ha) and pond (0.08 ha) systems were used. Water flowing into the Seokmoon estuarine reservoir from the Dangjin stream was pumped into wetland system. Water depth was maintained at 0.3 ${\sim}$ 0.5 m and hydraulic retention time was managed to about 2 ${\sim}$ 5 days; emergent plants were allowed to grow in the wetlands. After three growing seasons of the construction of wetlands, plant coverage was about 90%, even with no plantation, from bare soil surfaces at the initial stage. During the start up period of constructed wetlands, lower water levels should be maintained to avoid flooding newly plants, if wetland plants are to be started from germinating seeds. Effluent T-N concentration in low plant coverage wetland was higher in winter than high plant coverage wetland, whereas no T-P effluent concentration and removal efficiency difference was observed within 15% plant coverage. Dead vegetation affected nitrogen removal during winter because it is a source of organic carbon which is an essential parameter in denitrification. Biomass harvesting is not a realistic management option for most constructed wetland systems because it could only slightly increase the removal rate and provide a minor nitrogen removal pathway due to lack of organic carbon.

The Effect of Corporate Social Responsibilities on the Quality of Corporate Reporting (기업의 사회책임이 기업경영보고의 질에 미치는 영향)

  • Jeong, Kap-Soo;Park, Cheong-Kyu
    • Journal of Distribution Science
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    • v.14 no.6
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    • pp.75-80
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    • 2016
  • Purpose - A growing demand for sustainability reporting has placed pressure on firms with non-financial information that affects firm valuation, growth, and development. In particular, a number of researchers have investigated various topics in Corporate Social Responsibility (CSR), non-financial information. Prior studies suggest that CSR may affect corporate outcomes like corporate reporting, financial performance, and disclosures. However, the results from prior studies are not clear whether CSR affects corporate outcomes. This is partially due to the measurement issues with CSR. In this study, we examine whether CSR affects the quality of corporate reporting, one of the popular measures in corporate outcomes. We find an evidence that CSR positively affects the quality of corporate reporting. Research design, data, and methodology - In this study, we collected a unique dataset of CSR from MSCI. Total 169 firms listed in the Korean Stock Exchange from 2011 to 2014 were collected and analysed with the detailed CSR reports. Using a correlation test, we found a weak association between CSR and the quality of corporate reporting. However, the regression tests provided a strong relationship between CSR and the quality of corporate reporting after controlling for other variables that may affect the quality of corporate reporting. Additionally, we calculated the t-statistics based on heteroskedaticity-consistent standard errors (White, 1980). Results - Before we run the regression test, we sort the measures of the two dependent variables into each rating of CSR (from AAA to CCC). The results indicate that the quality of corporate reporting measured by discretionary accruals and performance-matched discretionary accruals monotonically decrease as the CSR ratings increase. This supports our hypothesis. In the regression tests, the coefficient on MJDA (PMDA) is -0.183 (-0.173) and significant at the 5% level. We can interpret the results as CSR affecting the quality of corporate reporting in positive ways. Other coefficients on control variables are consistent with prior studies. For example, the coefficients on both LOSS and LEV are positive and significant at conventional level, meaning that firms with financial difficulty may harm their quality of corporate reporting. Conclusion - We found an evidence that CSR is positively associated with the quality of corporate reporting. This study contributes to the literature in various ways. First, this study extends the line of CSR research by providing additional evidence in the setting of ethical behaviors by managements. This is consistent with the hypothesis and supports the results of prior studies. Second, to the best of my knowledge, this is the first study using the MSCI CSR ratings. In contrast with prior studies using different measures of CSR, the MSCI CSR ratings allow us to provide in-depth analysis. Third, the additional measure of dependent variable (PMDA) allows us to improve the robustness of our results. Overall, the results provided this study to extend the findings in prior studies by providing incremental evidence.

The Performance of the Combined Operation of Sprinkler and Smoke Curtain for Smoke Control in the Sloped Stairway Corridor (경사통로로 전파되는 연기에 대한 스프링클러와 제연커텐의 통합제연성능)

  • Jeon, Heung-Kyun;Choi, Young-Sang;Choo, Hong-Lok
    • Fire Science and Engineering
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    • v.20 no.4 s.64
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    • pp.1-12
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    • 2006
  • In this study, CFD computer simulations by FDS are carried out in order to confirm the performance of the combined operation of both sprinkler system and smoke curtain of 0.54 m depth installed for cooling and blocking the smoke which propagates beneath the sloped ceiling of a stairway corridor of which dimensions are 17.92 m long, 4.00 m wide, and 6.12 m high. It is shown that the response time of sprinklers decreases with fire size and it increases more about 1.1 second in case without smoke curtain than in case with smoke curtain, that the time of smoke transport from the fire source to the stairway outlet decreases considerably with fire size, and that the delay effect of smoke transport is not related to the sprinkler system, whether it is operated or not. This study shows that the combined operation of both sprinkler system and smoke curtain is very effective in smoke cooling, but it is a little for effect on smoke blockage. Although the hazard of skin burn due to radiative heat flux from hot smoke layer is decreased by spray cooling effect, the hazard of smoke suffocation and the weakening of visibility is increased by smoke downdrag and the turbulence of smoke-air mixing due to water spray. These conditions may result in preventing occupants from going out of the stairway during evacuation.

A Qualitative Study on the Drinking Experience of Participants in Self-Sufficiency Program with Alcohol Problems (음주문제가 있는 자활근로사업 참여자의 음주경험에 관한 질적연구)

  • Lee, Eun-Hee
    • The Journal of the Korea Contents Association
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    • v.21 no.10
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    • pp.723-737
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    • 2021
  • This study attempted to understand the meaning and nature of the drinking experience of participants participating in self-sufficiency program with alcohol problems. For this, data were collected by conducting in-depth interviews with seven problem drinkers currently participating in the self-support work project at the local self-support center. It was analyzed by a phenomenological analysis method. As a result of the study, 26 topics, 7 thematic vowels, and 3 categories were derived. The essential meaning of the study participant's drinking experience is as follows. It turned out to be 'a sense of accomplishment and belonging to job performance', 'extension of work life', 'maintaining social relations', 'weekly control drinking for self-support', 'minimum effort not to damage the working environment', 'self-criticism and reflection on absence from work resulting from heavy drinking', 'self-awareness of drinking problems. Through the analysis, the participants drank with a sense of accomplishment and a sense of belonging to job performance, and drinking was considered to extend their work life and maintain social relationships. At the same time, on weekdays when participating in self-support work projects, they we refrain from drinking in their own way and make minimal efforts not to interfere with the working environment under a hangover. The Absent from work due to heavy drinking led to self-reflection and furthermore, it was confirmed that they were aware of their problem drinking.

Effects of arginine and guanidinoacetic acid with or without phenylalanine on ascites susceptibility in cold-stressed broilers fed canola meal-based diet

  • Negin Delfani;Mohsen Daneshyar;Parviz Farhoomand;Younes Ali Alijoo;Sina Payvastegan;Gholamreza Najafi
    • Journal of Animal Science and Technology
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    • v.65 no.1
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    • pp.69-95
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    • 2023
  • In order to evaluate the effects of ARG sources (arginine [ARG] and Guanidinoacetic acid [GAA]) and phenylalanine (PHE) supplementation on performance, susceptibility to ascites, intestinal morphology, and nutrient digestibility in the cold-stressed broilers fed a canola meal (CM)-based diet, a 2×2 factorial experiment with four treatments was conducted. The dietary treatments included CM-based diet + 2.57 g/kg ARG, CM-based diet + 2.57 g/kg ARG + 1.5 g/kg PHE, CM-based diet + 1.8 g/kg GAA and CM-based diet + 1.8 g/kg GAA + 1.5 g/kg PHE. The corn-CM diet without supplementation was used as a negative control (NC) group in the fifth treatment that excluded the factorial arrangement. The results showed that adding ARG to diets without PHE supplement increased (p < 0.05) feed intake. Also, birds fed diets containing ARG had higher (p < 0.05) body weight gain (BWG) compared to those fed GAA added diets. Supplementation of PHE improved (p < 0.05) the FCR compared to groups fed diets without added PHE. Further, ARG addition increased (p < 0.05) plasma nitric oxide (NO) concentration, carcass, breast and leg yields, duodenal, jejunal, and ileal villus height (VH) to crypt depth (CD, and dry matter digestibility, while decreasing (p < 0.05) ascites mortality and right ventricle (RV) to total ventricle (TV) ratio compared to GAA added groups. Supplementation of PHE also declined susceptibility to ascites by reducing (p < 0.01) RV to TV ratio while increasing (p < 0.05) plasma NO level. The digestibility of ether extract also increased (p < 0.05) in broilers fed GAA supplemented diets versus those fed ARG added diets. The findings suggested that ARG may improve BWG and lower ascites incidence in broilers fed a diet based on CM under cold stress because of its antihypertensive effects. Moreover, the findings of this study demonstrated the importance of including PHE formulation in ARG-deficient diets to attenuate the adverse effects of cold stress on broilers. It was also concluded that GAA could be efficaciously used in cold-stressed broilers fed an ARG-deficient diet.

A Fusion Sensor System for Efficient Road Surface Monitorinq on UGV (UGV에서 효율적인 노면 모니터링을 위한 퓨전 센서 시스템 )

  • Seonghwan Ryu;Seoyeon Kim;Jiwoo Shin;Taesik Kim;Jinman Jung
    • Smart Media Journal
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    • v.13 no.3
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    • pp.18-26
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    • 2024
  • Road surface monitoring is essential for maintaining road environment safety through managing risk factors like rutting and crack detection. Using autonomous driving-based UGVs with high-performance 2D laser sensors enables more precise measurements. However, the increased energy consumption of these sensors is limited by constrained battery capacity. In this paper, we propose a fusion sensor system for efficient surface monitoring with UGVs. The proposed system combines color information from cameras and depth information from line laser sensors to accurately detect surface displacement. Furthermore, a dynamic sampling algorithm is applied to control the scanning frequency of line laser sensors based on the detection status of monitoring targets using camera sensors, reducing unnecessary energy consumption. A power consumption model of the fusion sensor system analyzes its energy efficiency considering various crack distributions and sensor characteristics in different mission environments. Performance analysis demonstrates that setting the power consumption of the line laser sensor to twice that of the saving state when in the active state increases power consumption efficiency by 13.3% compared to fixed sampling under the condition of λ=10, µ=10.

The Development of Multi-channel Electrical Conductivity Monitoring System and its Application in the Coastal Aquifer (다채널 전기전도도 모니터링 시스템의 개발과 연안지역 공내수 모니터링에 대한 적용 사례)

  • Shin, Je-Hyun;Hwang, Se-Ho;Park, Kwon-Gyu;Park, Yun-Seong;Byun, Joong-Moo
    • Geophysics and Geophysical Exploration
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    • v.8 no.2
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    • pp.156-162
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    • 2005
  • Particularly in research related to seawater intrusion the change of fluid electrical conductivity is one of major concerns, and effective monitoring can help to optimize a water pumping performance in coastal areas. Special considerations should be given to the mounting of sensors at proper depth during the monitoring design since the vertical distribution of fluid electrical conductivity is sensitive to the characteristics of seawater intrusion zone. This tells us the multi-channel electrical conductivity monitoring is of paramount consequence. It, however, is a rare event when this approach becomes routinely available in that commonly used commercial stand-alone type sensors are very expensive and inadequate for a long term monitoring of electrical conductivity or water level due to their restricted storage and difficulty of real-time control. For this reason, we have developed a real-time monitoring system that could meet these requirements. This system is user friendly, cost-effective, and easy to control measurement parameters - sampling interval, acquisition range, and others. And this devised system has been utilized for the electrical conductivity monitoring in boreholes, Yeonggwang-gun, Korea. Monitoring has been consecutively executed for 24 hours, and the responses of electrical conductivity at some channels have been regularly increased or decreased while pumping up water. It, with well logging data implemented before/after pumping water, verifies that electrical conductivity changes in the specified depths originate from fluid movements through sand layer or permeable fractured rock. Eventually, the multi-channel electrical conductivity monitoring system makes an effective key to secure groundwater resources in coastal areas.

Modeling of CO2 Emission from Soil in Greenhouse

  • Lee, Dong-Hoon;Lee, Kyou-Seung;Choi, Chang-Hyun;Cho, Yong-Jin;Choi, Jong-Myoung;Chung, Sun-Ok
    • Horticultural Science & Technology
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    • v.30 no.3
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    • pp.270-277
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    • 2012
  • Greenhouse industry has been growing in many countries due to both the advantage of stable year-round crop production and increased demand for fresh vegetables. In greenhouse cultivation, $CO_2$ concentration plays an essential role in the photosynthesis process of crops. Continuous and accurate monitoring of $CO_2$ level in the greenhouse would improve profitability and reduce environmental impact, through optimum control of greenhouse $CO_2$ enrichment and efficient crop production, as compared with the conventional management practices without monitoring and control of $CO_2$ level. In this study, a mathematical model was developed to estimate the $CO_2$ emission from soil as affected by environmental factors in greenhouses. Among various model types evaluated, a linear regression model provided the best coefficient of determination. Selected predictor variables were solar radiation and relative humidity and exponential transformation of both. As a response variable in the model, the difference between $CO_2$ concentrations at the soil surface and 5-cm depth showed are latively strong relationship with the predictor variables. Segmented regression analysis showed that better models were obtained when the entire daily dataset was divided into segments of shorter time ranges, and best models were obtained for segmented data where more variability in solar radiation and humidity were present (i.e., after sun-rise, before sun-set) than other segments. To consider time delay in the response of $CO_2$ concentration, concept of time lag was implemented in the regression analysis. As a result, there was an improvement in the performance of the models as the coefficients of determination were 0.93 and 0.87 with segmented time frames for sun-rise and sun-set periods, respectively. Validation tests of the models to predict $CO_2$ emission from soil showed that the developed empirical model would be applicable to real-time monitoring and diagnosis of significant factors for $CO_2$ enrichment in a soil-based greenhouse.