• Explosives and Blasting
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• v.23 no.2
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• pp.57-66
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• 2005

A major concern with blasting at surface mines is generation of ground vibration, air blast, flyrock, dust & fume and their impact on nearby structures and environment. A study was conducted at a coal mine in India which produces 10 million tonne of coal and 27 million cubic meter of overburden per annum. Draglines and shovels with dumpers carry out the removal of overburden. Detonation of 100 tonnes of explosives in a blasting round is a common practice of the mine. These large sized blasts often led to complaints from the nearby inhabitants regarding ground vibrations and their affects on their houses. Eighteen dragline blasts were conducted and their impacts on nearby structures were investigated. Extended seismic arrays were used to identify the vibration characteristics within a few tens meters of the blasts and also as modified by the media at distances over 5 km. 10 to 12 seismographs were deployed in an array to gather the time histories of vibrations. A signature blast was conducted to know the fundamental frequency of the particular transmitting media between the blast face and the structures. The faster decay of high frequency components was observed. It was also observed that at distances of 5km, the persistence of vibrations in the structures was substantially increased by more 10 seconds. The proximity of the frequency of the ground vibration to the structure's fundamental frequencies produced the resonance in the structures. On the basis of the fundamental frequency of the structures, the delay interval was optimized, which resulted into lower amplitude and reduced persistence of vibration in the structures.

• The Journal of the Convergence on Culture Technology
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• v.6 no.3
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• pp.393-399
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• 2020

In this study, the subsidence behavior caused by groundwater ex-flow in a limestone cavity encountered during tunnel excavation was quantified based on numerical analysis and the effect was analyzed. Based on the groundwater level and surface subsidence surveyed at the site, a numerical analysis technique was applied to analyze the characteristics of the subsidence behavior according to the tunnel passage of the geological vulnerabilities. The results of groundwater seepage-coupled analysis were analyzed to reflect the actual ground subsidence behavior. As a result of the study, it was analyzed that the ground subsidence due to the tunnel excavation in the limestone common section(the geological vulnerable zone) was analyzed that the dramatical decrease in groundwater level was the main cause. As a result of numerical analysis, it was analyzed that the long-term cumulative settlement of the asphalt surface after the groundwater ex-flow was 76~118mm due to the reduction of the volume of the soil layer due to the decrease in the groundwater level, and the settlement amount increased as the depth of the soil layer increased.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.12 s.115
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• pp.1189-1198
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• 2006

We analyze the radiated emission and mutual coupling problem from a single microstrip transmission line and double signal traces with various ground patterns. In this paper, it is shown that the reduction of the radiated emission from the signal traces can be accomplished by using the novel and compact patterns on the ground planes in a specific frequency band. The accuracy and validation of radiation mechanism from the transmission line on a novel ground plane are evaluated and explained by using a commercially available software and experiment, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.9
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• pp.1015-1022
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• 2007

In this paper, we proposed a wideband design of planar inverted-F antenna(PIFA) using two-layer, patches and modified ground structure. The antenna consists of two layer patches with common feed and modified ground plane to control resonance frequency and antenna input impedance. The measured bandwidth is 1,492 MHz(BW: 67.7 %, 1,457${\sim}2,949$ MHz) for VSWR<2, and 1,170 MHz(BW: 21 %, 4,970${\sim}$6,140 MHz) for VSWR<2.5. It covers service bands of DCS1800, DCS1900, UMTS(WCDMA), WiBro, WLAN(IEEE 802.11b), satellite DMB. WLAN(IEEE 802.11a) in Korea and radiation patterns shows constant figure with frequency change.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.1
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• pp.141-148
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• 2008

This paper presents experimental results on the safety of persons and protection of low-voltage equipments of the sub-station due to a single-phase ground fault in 22.9 kV-Y distribution system. In order to evaluate the hazard voltages and the stress voltage of the low-voltage(LV) equipment due to faults between high-voltage systems and earth based on the newly prescribed KS C IEC 60364 standard series, the verification tests in a 22.9[kV] neutral multiple grounding system were carried out. From the experimental results, we introduce serious problems causing some discomfort when applying KS C IEC 60364 standard series to the existing domestic distribution system and the effective protective measures against temporary overvoltages due to a ground fault in the common grounding which is combined the 22.9 kV-Y grounding and the customer's installation grounding are proposed. As a consequence, it was found that the equipotential bonding is an important prerequisite for the effectiveness of the protective measures for the safety of persons and LV equipment in the combined 22.9 kV-Y and low-voltage grounding system.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.2
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• pp.163-174
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• 2021

Heatwaves are one of the most common phenomena originating from changes in the urban thermal environment. They are caused mainly by the evapotranspiration decrease of surface impermeable areas from increases in temperature and reflected heat, leading to a dry urban environment that can deteriorate aspects of everyday life. This study aimed to calculate daily maximum ground surface temperature affecting heatwaves, to quantify the effects of urban thermal environment control through water cycle restoration while validating its feasibility. The maximum surface temperature regression equation according to the impermeable area ratios of urban land cover types was derived. The estimated values from daily maximum ground surface temperature regression equation were compared with actual measured values to validate the calculation method's feasibility. The land cover classification and derivation of specific parameters were conducted by classifying land cover into buildings, roads, rivers, and lands. Detailed parameters were classified by the river area ratio, land impermeable area ratio, and green area ratio of each land-cover type, with the exception of the rivers, to derive the maximum surface temperature regression equation of each land cover type. The regression equation feasibility assessment showed that the estimated maximum surface temperature values were within the level of significance. The maximum surface temperature decreased by 0.0450℃ when the green area ratio increased by 1% and increased by 0.0321℃ when the impermeable area ratio increased by 1%. It was determined that the surface reduction effect through increases in the green area ratio was 29% higher than the increasing effect of surface temperature due to the impermeable land ratio.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.306-313
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• 2012

In order to enhance the isolation level between two dual-band E-slot microstrip patch antennas, EBG structure which operates in UMTS Tx(1.92~1.98 GHz) and Rx(2.11~2.17 GHz) band is proposed. The proposed EBG structure made with a periodic array of two different size EBG unit cells which has a modified mushroom-type for isolation improvement between two antennas. They do not share a common ground plane of the microstrip patch antenna. Overall size of the fabricated antenna is $210.5mm{\times}117mm$. The two different EBG unit cell sizes are $15.6mm{\times}4mm$ and $17.4mm{\times}4mm$, respectively. It was etched on the FR-4 substrate(thickness=3.93 mm, ${\varepsilon}_r$=4.6). The experiment results show that the isolation level between antennas in Tx/Rx band were improved by about 9 dB and 12 dB, respectively, through the use of the proposed EBG structure.

• The Journal of Fisheries Business Administration
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• v.11 no.1_2
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• pp.115-155
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• 1980

Nowadays managers of fisheries enterprises and users of accounting information have a considerable interest in the fishery right. The fishery right, which is given by administrative quarters, is referred to exclusive fishing right in a certain coastal fishing ground, and it has been one of the property rights since the turn of the century. The main purpose of this study is to provide an improved accounting method of the fishery right from the side of accounting. To achieve this purpose, legal nature of the fishery right should be understood in the first place, for the fishery right, an intangible asset, is a sort of property right guaranteed by the fisheries laws, According to the basic law in the fisheries "Fisheries Law, " the fishery right is broken down largely into three categories; culture fishing right, set fishing right and common fishing right. The legal characteristics of these fishery rights are as followings: 1. The fishery right is a private right. 2. The fishery right is a property right. 3. The fishery right is a right in rem, and legal provisions pertaining to land are applied to the fishery right with necessary modifications. In addition to the above fishery rights, the Fisheries Law provides some provisions on the so-called entrance right, and those who obtained the right are authorized to access to a certain common fishing right fishing ground where they have been traditionally fishing. In the inland fisheries, the fishery right system similar to that of the coastal fisheries discussed above is adopted in conformity with the Inland Fisheries Developing and Expediting Law. Viewing from an angle of accounting, there are two kinds of additional fishing rights which are dealt as assets. These fishery rights dealt as asset include the license of entry in the so-called permitted fishing which is also called as fishery right in plain language, and tile entrance right obtained abroad. Although these two kinds of rights are not the fishery right from a viewpoint of law, they are regarded as fishing rights in accounting which intends to provide a useful economic information.formation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8927-8932
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• 2015

A directional feeding method at the railway transformer is applied for supplying the power to the electric railway substations, and the pre-installed facilities with common feeder are utilized in preparation for the failure of feeding system and in finding a fault location in case that the catenary failure occurs. However, it is some difficulty in finding the fault location since there is an interface problem with the facilities when the supplying power system operates. In this paper, Auto Fault Locator Transfer Drive System (ALTDS) is designed to search for the fault location efficiently, and the measuring data are obtained and compared with the KORAIL standards. Further, the ground connection test is accomplished 24 times as the verification method, and it is shown that the methodology provides better performance than the existing traditional one.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.2
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• pp.302-312
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• 2012

In this paper, small-area and high-reliability design techniques of a 512-bit EEPROM are designed for UHF RFID tag chips. For a small-area technique, there are a WL driver circuit simplifying its decoding logic and a VREF generator using a resistor divider instead of a BGR. The layout size of the designed 512-bit EEPROM IP with MagnaChip's $0.18{\mu}m$ EEPROM is $59.465{\mu}m{\times}366.76{\mu}m$ which is 16.7% smaller than the conventional counterpart. Also, we solve a problem of breaking 5V devices by keeping VDDP voltage constant since a boosted output from a DC-DC converter is made discharge to the common ground VSS instead of VDDP (=3.15V) in getting out of the write mode.