• The Journal of Fisheries Business Administration
• /
• v.48 no.1
• /
• pp.1-16
• /
• 2017

The fisheries industry has led the Korean economy, and has been achieving high-level position in the world. However, this industry meets aging, low growth and profit. In order to overcome this critical situation, it is needed to understand the overall status of industry. In industry level, most of previous researches focused on ocean industry rather than fisheries. In addition, scholars have been getting a lot of attention about fisheries cooperatives, fishing-ports, methods of fishery, and manufacturing process in fisheries sector. The aim of this research is analysis of domestic fisheries industry's managerial performance using data envelopment analysis(DEA) considering operating and scale view. Furthermore, the comparative analysis is performed by firm size, and industry type. In results, fisheries industry's managerial performance is not high, overall. In more detail, most of big size firms are under decreasing returns to scale(DRS) status. Fishery processing industry's performance is low, and fishery distribution industry has the best performance. This paper suggests that transferring operating capability from big firms to small firms, and policy supports and firm's activities should be accompanied for high-value added in fisher, and fishery processing industries.

• The KSFM Journal of Fluid Machinery
• /
• v.20 no.2
• /
• pp.69-74
• /
• 2017

Sodium hypochlorite, used as water disinfectant, is generated by electrolysis of salt. Compared to chlorine gas disinfection, it is free from high-pressure gas regulation and does not generate toxic gas, so it is increasingly used as a safe disinfectant. Despite these advantages, the concentration of sodium hypochlorite decreases with temperature during long-term storage, and the amount of chlorate increases when a large amount is added, it has mainly been applied to small-scale waterworks. To solve this problem, high sodium hypochlorite generation was developed. In this study, the changes of concentration and chlorate of sodium hypochlorite with time has been studied. As a result of the test, it was found that the usable period of sodium hypochlorite produced at a certain temperature or less was increased from 1.5 days to 13 days. Overall, sodium hypochlorite can be applied even in large-scale waterworks, which makes operation more stable and also reduces the disinfection byproducts, thus it contributed greatly to securing water quality.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.22 no.4
• /
• pp.55-60
• /
• 2018

The thermal property is one of the most important characteristics in the field of energetic materials. Because energy materials release decomposition heat, differential scanning calorimetry (DSC) is frequently used for thermal analysis. However, thermodynamic events, such as melting can interfere with DSC kinetic analysis. In this study, we use isothermal mode for DSC measurement to avoid thermodynamic issues. We also merge accelerating rate calorimetry(ARC) data with DSC data to obtain a robust prediction results for small scale samples and for large scale samples as well. For the thermal property prediction, advanced kinetics and technology solutions(AKTS) programs are used.

• Wind and Structures
• /
• v.32 no.4
• /
• pp.371-391
• /
• 2021

Tornadoes are the most devastating meteorological natural hazards. Many empirical and theoretical numerical models of tornado vortex have been proposed, because it is difficult to carry out direct measurements of tornado velocity components. However, most of existing numerical models fail to explain the physical structure of tornado vortices. The present paper proposes a new empirical numerical model for a tornado vortex, and its load effects on a low-rise and a tall building are calculated and compared with those for existing numerical models. The velocity components of the proposed model show clear variations with radius and height, showing good agreement with the results of field measurements, wind tunnel experiments and computational fluid dynamics. Normal stresses in the columns of a low-rise building obtained from the proposed model show intermediate values when compared with those obtained from existing numerical models. Local forces on a tall building show clear variation with height and the largest local forces show similar values to most existing numerical models. Local forces increase with increasing turbulence intensity and are found to depend mainly on reference velocity Uref and moving velocity Umov. However, they collapse to one curve for the same normalized velocity Uref / Umov. The effects of reference radius and reference height are found to be small. Resultant fluctuating force of generalized forces obtained from the modified Rankine model is considered to be larger than those obtained from the proposed model. Fluctuating force increases as the integral length scale increases for the modified Rankine model, while they remain almost constant regardless of the integral length scale for the proposed model.

• Journal of People, Plants, and Environment
• /
• v.24 no.6
• /
• pp.551-561
• /
• 2021

Background and objective: Vietnam is prioritizing agricultural production for food export capacity in all national policies. As a result, for three decades, its agriculture has been making quite many remarkable achievements. Methods: The most successful one is that the nation has become one of the world's leading rice exporters and ensures its national food security. Through these endeavors, the Mekong River Delta (MRD), in particular, has emerged as a key region in ensuring national food security and rice export. Results: The new era can now see Vietnamese agriculture turning to place special emphasis on commodity quality and the improvement of the living environment. This is evidenced, for example, by the phenomenon that the MRD, as a rice basket of the whole country, is making moves back to nature-based agriculture with attempts to restore the natural ecology, including preserving and restoring local traditional rice seeds, adopting natural farming practices and minimizing the use of chemical fertilizers and pesticides. Conclusion: The case studies of nature-based farming practices in the MRD indicate that, while the national agriculture is generally developing large-scale production, the small-scale farming in the region, integrated with tourist and educational activities on-site, is meeting the demands of a highly potential domestic niche market. Moreover, this model appears to be a sustainable farming approach that defines itself as a working green livelihood for the region.

• The Journal of Internal Korean Medicine
• /
• v.27 no.2
• /
• pp.371-378
• /
• 2006

Objectives : The aim of this study is to review the effects of acupuncture on lower limb spasticity control in stroke patients. Methods: H-reflex/M-response ratio and Modified Ashworth Scale was used for evaluation of spasticity control before acupuncture, within one hours after acupuncture , at twenty-four hours, and four weeks. We divided two groups. One is the yin meridian acupunctured goup and the other is the yang meridian acupunctured group. Results: H/M ratio is declined within 1 or 24 hours after acupuncture for poststroke spasticity patients. The yin meridian acupunctured group is a bit more efficient than the yang meridian acupunctured goup. But there is no meaning in the statistics because of small patient pool. Conclusions: We need more patients group to decide the effect of electro- acupuncture on leg spasticity of stroke patients.

• Food Science and Biotechnology
• /
• v.14 no.4
• /
• pp.446-449
• /
• 2005

Two single-magnetron heating systems (SM-HS), each with a helical glass heat exchanger and a cylindrical cavity, were combined to make a two-magnetron-in-series heating system (2MS-HS) in order to increase the heating capacity. A comparison using water showed that the heating performance of the 2MS-HS was increased by two-fold as compared to that of the SM-HS, resulting in energy saving of 7.0% in 2MS-HS. Pasteurization test of 2MS-HS conducted with model food (LB broth contaminated with Bacillus subtilis) showed two-fold higher treatment capacity compared to SM-HS. Relationships between outlet temperature of the processed food, flow rate, and residence time in the 2MS-HS were established for water. Optimum pasteurization capacity was 17 s, $73^{\circ}C$, at flow rate of 280 ml/min. The 2MS-HS could be applied to the small-scale pasteurization of liquid food.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.34 no.4
• /
• pp.383-390
• /
• 2010

In this study, a thermoelectric power generation system was constructed for a waste-heat recovery. Thermoelectric modules were attached to a stainless steel duct, and a hot air blower was set such that it faced the duct inlet. We found that to achieve the maximum power out of the system, the temperature in the hot side of the thermoelectric module should be uniform. The optimum compressive pressure exerted on the module was observed. Further, the thermoelectric power performance was evaluated using the heat sink attached to the cold side of the thermoelectric module. In particular, when using a natural-convection heat sink, the power output difference is approximately five times.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.22 no.4
• /
• pp.181-188
• /
• 2010

The objectives of this study are to analyze the possibility of the landfill gas recycling for the middle and small scale landfills where the recycling facilities are not installed in Korea. It was found that the power generation plants by landfill gas were installed in domestic 15 landfills and the gas engine generation was adopted in 14 places. As the result of economic analysis, the landfill gas recycling is found to be available in 12 places and CERs of 153,693 $tCO_{2e}$ can be secured per year. Through the reduction of the air pollutants and VOCs, the social benefits of 730 million won accrue per year. Also, the power production of 18.8 GWh will substitute the crude oil imports of 4,048 TOE and the revenue of 2.49 billion won is expected to power trading. It is also found that the power generation plants by landfill gas will give the social benefits such as the reduction of the environmental problems and the substitution effect of crude oil imports.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.23 no.9
• /
• pp.620-626
• /
• 2011

The purpose of this study is to evaluate a simulation model of a stacking guidance system (SGS) with a roller guide applicable to the mobile harbor. The study used a small-scale model (1/20) made of wood with rollers in order to compare the dynamic analysis with experiment results. The law of similarity was applied for the validation of the scaled model. In order to construct a more realistic simulation model, the damping coefficient of the dynamic model was adjusted to 0.5 Ns/mm for the wood-to-wood contact condition based on the experimental results. Using this validated model, dynamic simulations were also carried out for containers of 20, 30, and 40 tons. The results showed that the reaction force of the roller guide was increased from 74.7 kN to 91.2 kN as the weight of container increased. For the design of a roller guide for SGS, the results obtained in this study can be used to reduce the reaction force by employing a rubber roller or a highly damped rotational joint.