• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.639-652
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• 2023

The fundamental background behind the introduction of the fishing vessel system is to allow petty small fishers to engage in pure fishery business activities with fishing vessels during normal times and engage in fishing vessel business only during specific periods (closed fishing season, etc.) thereby granting a qualification as an auxiliary tool for the economic activities of petty small fishers. In addition, fishing boats are allowed to engage in excursion ship activities using fishing vessels registered under the Fishing Vessels Act, the form of fishing vessels should also have a general and universal structure that is practically easy to engage in fishing activities in the field in accordance with the relevant regulations. However, most fishing vessel proprietors are currently focusing only on increasing income, and rather than building fishing vessels in a reasonable form suitable for the original purpose of general fishing vessels, they prefer an abnormal hull form equivalent to expediency, that is biased hull structure biased toward the fishing vessel business. As a result, it is causing serious problems in safety management as well as conflict [damaging relative equity in government support measures (tax-free oil supply, etc.), and depletion of livelihood-type fish stocks] with fishing vessel forces who consider the fishing vessel business only to be a part of the side job among all fishery business activities. Meanwhile, the most fundamental cause of this problem is that the current Fishing Management and Promotion Act, limits the concept of fishing vessels to fishing vessels registered under the Fishing Vessels Act, and applies survey standards accordingly. Accordingly, in this study, through analysis of the distribution status of fishing vessels, structural characteristics, operation status of fishing vessels, and the government's fishing promotion policies, etc., the relevant laws (regulations) have been reorganized to suit the current reality of the concept of fishing vessels to separate the current fishing vessel from fishing vessels and operate it as a fishing-only vessel.

• The Journal of the Acoustical Society of Korea
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• v.30 no.4
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• pp.215-222
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• 2011

In order to obtain high resolution images, a focusing ultrasonic transducer operated in very high frequency (VHF) range was fabricated and its characteristics were evaluated. A 9-${\mu}m$ thick PVDF film with only one metalized surface for electric ground was adhered to a CCP (Copper-clad polyimide) film by using epoxy. It was pressed by a metal ball to form a concave surface and its rear side was filled with the epoxy. The radius of curvature and the f-number of the fabricated transducer are 7.5 mm and 1.7, respectively. The pulse-echo measurement results from a target located at the focal point showed that the frequency bandwidth was 35.0 MHz and the insertion loss near the peak frequency of approximately 40 MHz was about 60 dB. Those values agreed well with the simulation results by the KLM equivalent circuit analysis including the effect of the epoxy bonding layer. When the image of thin copper lines by the 35 MHz transducer of the UBM (Ultrasonic Backscattering Microscope) system was compared with the image by the transducer fabricated in this study, the fabricated transducer was observed that the axial resolution was improved although the lateral resolution was degraded.

• Magazine of the Korea Concrete Institute
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• v.7 no.3
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• pp.187-198
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• 1995

This paper develops practical and reallstic reliabllity models and methods for the evaluation of system rehability and system rellabllity based ratlng of R.C box glrder bridge superstructures. The precise prediction of reberved carrying capacity of bridge as d system is extremely difficult especially when the brldges are highly redundant and slgnlficantly deter 1or;itcd or dainagetl. Thls papel proposes a nt2w approach for the evaluation of reseived system c,drrying capaaty of br~dges in terms ot equ~vdleiit system strength, which may b~ ddcflned as a brtdge system strength correipcmdlng tu the system rehability of the bridge. This cm be ticrAvcd from an Inverse process bami or1 the con~ept of FOSM(F1rst Order Second Moment) form of system reliabihty index. The sf rength llmt state models for K C box girder br~dges suggested In the paper dre based on the basi~ bending and shear strength And thc system reliatxllty pro,~lerri of box gritier super structure 1s formuldted as parallel serles models obtalncd f ~ o m thc FMA(Fdilure blode Rp proath) based on major failure mc>clmusrns or c~itlcal fdure ,>tatcs of each nuder .WOSM(Ad-vanced First Order Second Moment) and IST(1mportance Sampling Technique) simulation algorithm are used for the reliability analysis of the proposed models.

• Journal of the Korean Institute of Gas
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• v.24 no.3
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• pp.33-39
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• 2020

In general, in a batch reaction process in which products are made using flammable liquids, splash filling is used to clean the walls of the reactor by spraying flammable liquids, which are raw materials used for product, during cleaning of the reactor after work. During this process, mist of flammable liquid is generated, the lower limit of explosion is lowered, and fire·explosion may occur due to discharges caused by various types of complex charges, such as flow charge, collision charge, and ejection charge. Therefore, based on the recent accident case, to identify the risk when working in the form of splash filling with toluene in a batch process and perform an explosion impact analysis using the TNT equivalent method After that, we will analyze the accident results and suggest preventive measures such as constant purge system, improvement of cleaning method, and use of tantalum to prevent such accident.

• Magazine of the Korean Society of Agricultural Engineers
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• v.30 no.2
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• pp.31-43
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• 1988

The Purpose of this study is to develop the rainfall-delayed response model (RDR Model) which influences the baseflow proportion of rivers as a result of the antecedent precipitation of the previous several months. The assesment of accurate baseflows in the rivers is one of the most important elements for the planning of seasonal water supply for agriculture, water resources development, hydrological studies for the availability of water and design criteria for various irrigation facilities. The Palukan river gauging site which is located in the Pulukan catchment on Bali Island, Indonesia was selected to develop this model. The basic data which has been used comprises the available historic flow records at 19 hydrologic gauging stations and 77 rainfall stations on Bali Island in the study. The methology adopted for the derivation of the RDR model was the water balance equation which is commonly used for any natural catcbment ie.P=R+(catchment losses) -R+(ET+DP+DSM+DGW). The catchment losses consist of evapotranspiration, deep percolation. change in soil moisture, and change in groundwater storage. The catchment areal rainfall has been generated by applying the combination method of Thiessen polygon and Isohyetal lines in the studies. The results obtained from the studies may be summarized as follows ; 1. The rainfall-runoff relationship derived from the water balance equation is as shown below, assuming a relationship of the form Y=AX+B. Finally these two equations for the annual runoff were derived ; ARO$_1$=0.855 ARF-821, ARF>=l,400mm ARO$_2$=0.290ARF- 33, ARF<1,400mm 2. It was found that the correction of observed precipitation by a combination of Thiessen polygons and Isohyetal lines gave good correlation. 3. Analysis of historic flow data and rainfall, shows that surface runoff and base flow are 52 % and 48% (equivalent to 59.4 mm) of the annual runoff, respectively. 4. Among the eight trial RDR models run, Model C provided the correlation with historic flow data. The number of months over which baseflow is distributed and the relative proportions of rainfall contributing in each month, were estimated by performing several trial runs using data for the Pulukan catchment These resulted in a value for N of 4 months with contributing proportions of 0.45, 0.50, 0.03 and 0.02. Thus the baseflow in any month is given by : P$_1$(n) =0.45 P(n) +0.50 P(n-I ) +0.03 P(n-$_2$) +0.02 P(n-$_3$) 5. The RDR model test gave estimated flows within +3.4 % and -1.0 % of the observed flows. 6. In the case of 3 consecutive no rain months, it was verified that 2.8 % of the dependable annual flow will be carried over the following year and 5.8 % of the potential annual baseflow will be transfered to the next year as a result of the rainfall-delayed response. The results of evaluating the pefformance of the RDR Model was generally satisfactory.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.58
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• pp.215-236
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• 2013

It is quite true that the more Korean contractors receive overseas contracts, the more they need guarantees. The top market for them is the Middle East countries, consisting of more than the half of the total amount awarded last year and the trend is increasing as well. The problem, however, is that employers in these countries are reluctant to use international rules for guarantee such as URDG or ISP98 and easily make unfair callings. However, Korean contractors(applicants), especially small and medium sized enterprises(SMEs) tend to hurriedly enter a contract without looking into its contents as well as guarantees. They do not realize the importance of the guarantees until they receive callings from the employers(beneficiaries). Being independent from the underlying contracts, guarantee is the equivalent to cash in that it usually does not require any proof of demand when calling and the guarantor should make a payment within usually 5 business days after the request. It is often observed these days that several Korean SMEs go bankrupt due to liquidity risks after receiving unfair callings from employers in the Middle East countries. In retrospect, some cases could be obviated if contractors were a little more careful in checking the contents of a guarantee at the time of concluding a contract. For example, there is one case where the underlying contract includes a reduction clause in the Advance Payment bond and the guarantee does not have that clause. In the end, the Korean contractor had to take the whole burden of the bond amount though it had finished 81% of the project. Nobody could argue that contractors should take a full responsibility if they fail in their obligations. However, the employer's wrongful callings need to be prevented in the first place, if possible. As there shouldn't be a case where one party is at a disadvantage against the other like the case mentioned above, useful insight is being sought to minimize unfair calling risks for the benefit of the applicant. First, the applicant should carefully look into every detail of the potential guarantee before signing a contract, heeding especially that there is a reduction clause in the AP bond. Second, the governing principles for guarantee should be the ones that are internally used such as URDG758 that is objective in terms of callings given that, for example, it specifies that the requirement for a supporting statement when making a demand is a default rule. It is also recommended that the form of guarantees be the standard demand guarantee. Third, parties involved in issuing guarantees are advised to understand international rules for guarantee like URDG758 and ISP98 and to play a key role in guiding SME contractors in Korea so that they can protect themselves from possible wrongful callings, particularly from employers in the Middle East countries. I hope this study would give a wake-up call for Korean SMEs wishing to do business in the Middle East countries and remind them of the importance of guarantee itself and its governing principles.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.6
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• pp.476-484
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• 2017

The purpose of this paper is to verify the structural integrity of a region with numerous penetration-holes in offshore structures such as semi-submersible rig and FPSO. In order to effectively check the yielding and buckling strength of plate members with penetration-holes, a screening analysis program was developed with the FE analysis tool to generate fine meshed model using the theoretical and analysis methods. When a hole is appeared in the plate structure members, the flow of stress is altered such that concentrations of stress form near the hole. Stress concentrations are of concern during both preliminary and detail design and need to be addressed from the perspectives of strength. To configure the geometrical shape, very fine meshed FE analysis is needed as the most accurate method. However, this method is practically impossible to apply for the strength verifications for all perforated plates. In this paper, screening analysis method was introduced to reduce analysis tasks prior to detailed FE analysis. This method is applied to not only the peak stress calculation combined stress concentration factor with nominal stress but also nominal equivalent stress calculation considering cutout effects. The areas investigated by very fine meshed analysis were to be chosen through screening analysis without any reinforcements for penetration-holes. If screening analysis results did not satisfy the acceptance criteria, direct FE analysis method as the 2nd step approach were applied with one of the coarse meshed model considering hole or with the very fine meshed model considering the hole shape and size. In order to effectively perform the local fine meshed analysis, automatic model generating program was developed based on the MSC/PATRAN which is pre-post FE analysis program. Buckling strength was also evaluated by Common Structure Rule (CSR) adopted by IACS as the stress obtained from very fine meshed FE analysis. Due to development of the screening analysis program and automatic FE modeling program, it was able to reduce the design periods and structural analysis costs.

• Korean journal of applied entomology
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• v.56 no.1
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• pp.51-60
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• 2017

The striped fruit fly, Bactrocera scutellata, infests pumpkin flowers. Males are attracted to raspberry ketone (RK) and feed the attractant. This study was conducted to determine essential techniques to develop a male annihilation technique (MAT) of this insect pest. Effective attractants were screened in laboratory and field conditions. Both males and females were responsive to methyl eugenol (ME) in laboratory, though no flies were attracted to ME traps in field conditions. In contrast, cuelure (CL), which is a chemical derivative of RK, was effective to attract males of B. scutellata in both laboratory and field conditions. However, RK was equivalent or superior to CL when they were formulated in a form of wax dispenser. A pyrethroid insecticide along with the attractant was effective to attract and kill B. scutellata. Funnel trap was useful for MAT to confirm and count dead flies. These results indicate that MAT against B. scutellata consists of RK and bifenthrin in a wax type formulation, which is installed to a funnel type of trap. These essential factors would be useful to develop MAT applicable to control B. scutellata in fields.

• Journal of the Korea Concrete Institute
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• v.21 no.4
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• pp.401-408
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• 2009

A compression lap splice becomes an important issue due to development of ultra-high strength concrete. Current design codes regarding compression lap splice do not utilize merits of the improved strength of ultra-high strength concrete. Especially, a compression lap splice can be calculated longer than a tension lap splice according to the codes because they do not consider effects of compressive strength of concrete and transverse reinforcement. This anomaly confuses engineers in practice. Design equation is proposed for compression lap splice in 40 to 70 MPa of compressive strength of concrete. The proposed equation is based on 51 specimens conducted by authors. Basic form of the equation includes main parameters which are derived from investigating test results. Through two-variable non-linear regression analysis of measured splice strengths, a strength equation of compression lap splices is then derived. A specified splice strength is defined using a 5% fractile coefficient and a lap length equation is constructed. By the proposed equation, the anomaly of lap lengths in tension and compression is got rid of. In addition, the equation has a reliability equivalent to those of the specified strengths of materials.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.1
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• pp.62-68
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• 2012

Steady-State Visually Evoked Potentials (SSVEP) are natural response signal associated with the visual stimuli with specific frequency. By using SSVEP, occipital lobe region is electrically activated as frequency form equivalent to stimuli frequency with bandwidth from 3.5Hz to 75Hz. In this paper, we propose an experimental paradigm for analyzing EEGs based on the properties of SSVEP. At first, an experiment is performed to extract frequency feature of EEGs that is measured from the image-based visual stimuli associated with specific objective with affordance and object-related affordance is measured by using mirror neuron system based on the frequency feature. And then, linear discriminant analysis (LDA) method is applied to perform the online classification of the objective pattern associated with the EEG-based affordance data. By using the SSVEP measurement experiment, we propose a Brain-Computer Interface (BCI) system for recognizing user's inherent intentions. The existing SSVEP application system, such as speller, is able to classify the EEG pattern based on grid image patterns and their variations. However, our proposed SSVEP-based BCI system performs object pattern classification based on the matters with a variety of shapes in input images and has higher generality than existing system.