• Journal of Korean Society on Water Environment
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• v.34 no.2
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• pp.210-215
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• 2018

It is difficult to count colonial cyanobacteria Microcystis cells since the thickness of colonies is constrained by amorphous mucilage, making it impossible to estimate the number of cells. Disaggregation of Microcystis colonies into single cell is needed to improve the accuracy and precision of cell density estimation of naturally collected samples. Uultrasonic treatment method is commonly used owing to the simplicity and immediacy of the procedure. However, amplitude, frequency, and duration of ultrasonic treatment also cause cell loss during the experiment. Optimal ultrasonic treatment has not been standardized yet. Therefore, the objective of this study was to investigate optimal ultrasonic treatment by analyzing cell density and colony numbers. We collected colonial Microcystis from Changnyeong-Haman weir area in Nakdong River during harmful algal boom period from September to October in 2017. Ultrasonic treatment method was applied to disrupt colonies into single cells to enumerate cell density. Among treatment conditions, results from continuously treated for 100 seconds were found to be the optimum to reduce colonies to a suspension of single cell without cell losses under high and low density of Microcystis cells. Lugol iodine fixed cells followed by sonication showed less negative impact of cell damage within the optimal treatment time (100 seconds). Furthermore, disaggregated cells treated by sonication enables microscopic observation more easily since gas vacuoles were collapsed to facilitate sedimentation of cells under the counting chamber for quantitative enumeration of buoyant Microcystis cells.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.2
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• pp.235-238
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• 2020

In the smart home era, fire safety is very important for human life and facility safety. Casualties and property damage from the fire would be a huge national loss. In this paper, we propose to predict the risk by determining the operating time of the fire detector according to the fire in the smart home. Among IoT fire detectors, heat detectors and smoke detectors, the risk can be predicted due to the difference in the operating time depending on the fire. Based on the results of this experiment, the ion-type smoke detector shows very fast characteristics, so it would be good to use the results in future fire prevention facility.

• Convergence Security Journal
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• v.14 no.4
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• pp.109-116
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• 2014

Personal information leakage in financial corporations including three card corporations has occurred constantly this year. It is due to incomplete encryption system and negligent personal security. Solicitors are known as a cause of information leakage because they operate with leaked information. Information leakage can cause secondary damage with mental demage to person and result in a drop in reliability as well as an operating loss in financial corporations. Also because it can destroy a base of credit society, prevention of recurrence is badly needed. The government finally announced 'general measures for prevention of information leakage in the field of finance' with sanctions reinforcement and restriction to collect, possess, provide personal information as the main agenda. And a related law revision is going in the National Assembly. In this paper, effectiveness of government measures is weighed with the cause analysis of information leakage and countermeasure for prevention of information leakage is found.

• Journal of the Korean Society of Safety
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• v.26 no.2
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• pp.89-98
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• 2011

The traffic accidents at a construction site, which happen due to construction vehicles' frequent access to a construction site, its subsequent conflicts with ordinary vehicles and pedestrians, and inappropriate installation & management of traffic security facilities, have not many proportions in all traffic accidents, but obviously, the accident damage is quite serious when comparing the level of the fatal per one accident. This research conducted an analysis of traffic accident injury severity using Ordered Probit Model in relation to 241 traffic accident cases that occurred caused by construction sites among the traffic accidents that took place in Seoul and Gyeoggi-do region for two years from 2006 until 2007. As a result, the significant variables enough to explain traffic accident injury severity were analyzed to be the state of road surface, linear shape of an accident spot & whether the damaging car belongs to the vehicle for construction, and whether vehicles have access to a construction site at the time of an accident. Through this, this research found out some fact as follows: first, there need to be more aggressive management of the vehicles for construction and a year-round placement of the manpower who can control vehicular access to a construction site. Second, it is necessary to get drivers to recognize the fact that there exists a construction site on the construction section which is on the border of curved roads in advance to prevent a traffic accident, helping to reduce socioeconomic loss & costs incurred by a traffic accident.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.4
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• pp.323-333
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• 2005

Recently the fire is happening at the tunnel and underground - structure internationally. We are socially the economy the actual circumstances which serious loss is happening due to an fire occurrence when fire happened which is closed like tunnel and underground - structure, the collapse from the burglar degradation of strength of tunnel concrete lining and human life damage happen. It causes big problem while the long time disconnects a traffic network. While the fire happened in this research at the tunnel, the paper construct a basis data to deduce the specification regulation about stability of tunnel concrete lining. In this paper, the experiment was carried out for the prevention of explosive spalling of tunnel to use a reinforced Polypropylene concrete which mixes a Polypropylene which are known for the thing by being efficient at a protect of explosive spalling of the concrete. According to the firproof test result of reinforced Polypropylene admixture mortar, Polypropylene admixture of prevention of explosive spalling analyzed 0.2%-0.25%.

• BMB Reports
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• v.41 no.2
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• pp.153-157
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• 2008

The objective of the present study was to identify mitochondrial components associated with the damage caused by iron to the rat heart. Decreased cell viability was assessed by increased presence of lactate dehydrogenase (LDH) in serum. To assess the functional integrity of mitochondria, Reactive Oxygen Species (ROS), the Respiratory Control Ratio (RCR), ATP and chelatable iron content were measured in the heart. Chelatable iron increased 15-fold in the mitochondria and ROS increased by 59%. Deterioration of mitochondrial function in the presence of iron was demonstrated by low RCR (46% decrease) and low ATP content (96% decrease). Using two dimensional gel electrophoresis (2DE), we identified alterations in 21 mitochondrial proteins triggered by iron overload. Significantly, expression of the $\alpha$, $\beta$, and d subunits of $F_1F_o$ ATP synthase increased along with the loss of ATP. This suggests that the $F_1F_o$ ATP synthase participates in iron metabolism.

• The Journal of the Acoustical Society of Korea
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• v.20 no.5
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• pp.21-27
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• 2001

Impulsive sound and vibration signals in gear system are often associated with their faults. Thus these impulsive sound and vibration signals can be used as indicators in condition monitoring of gear system. The traditional continuous wavelet transform has been used for detection of impulsive signals. However, it is often difficult for the continuous wavelet transform to identify spikes at high frequency and meshing frequencies at low frequency simultaneously since the continuous wavelet transform is to apply the linear scaling (a-dilation) to the mother wavelet. In this paper, the spike wavelet transform is developed to extract these impulsive sound and vibration signals. Since the spike wavelet transform is to apply the non-linear scaling, it has better time resolution at high frequency and frequency resolution at low frequency than that of the continuous wavelet transform respectively. The spike wavelet transform can be, therefore, used to detect fault position clearly without the loss of information for the damage of a gear system. The spike wavelet transform is successfully is applied to detection of the gear fault with tip breakage.

• Journal of Sensor Science and Technology
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• v.23 no.3
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• pp.178-184
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• 2014

Key components of implantable hearing aids are consist of an acoustic sensor that collect external sound by suppressing the body noise, a signal processor module for compensation algorithm of hearing loss, and a output transducer which has tiny size but have high efficiency, respectively. In the partial implantable hearing aids, technologies of transducer and signal processor are so matured that can be applied not too much difficulty. However, due to the difficulties in implantable acoustic sensor technology, such as minimization of masticatory sound and damage of sensor's membrane from external impact, practical use of fully implantable hearing aids have not successful so far. In this paper, we have proposed a novel implantable acoustic sensor which has trans-tympanic structure, and is verified that the proposed method can be very useful for fully implantable hearing aids by cadaveric experiments.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.3
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• pp.367-374
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• 2009

Every year there are great socio-economic loss and damage caused by landslides in steep slopes. According to recent statistics, the percentage of casualty due to breakdown in steep slopes was 27.3% of all natural disasters occurring over the past decade($1998{\sim}2007$). Therefore, the nationwide scale survey on the landslide susceptibility was made to recognize the status quo for appropriate troubleshooting measure against the collapse of steep slopes. Nevertheless, few dent that the data collected is not sufficient to grasp the overall understanding of the onsite situation due to lack of spatial information. As a result, the study aims to develop a program enabling to send on site topological data and prefixed data-gather criteria directly to the central management server in real-time basis. It will be conducted through mobile devices and portable GPS system, accordingly. This program is expected to be implemented as an efficient application tool of slope spatial information acquisition.

• Applied Microscopy
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• v.13 no.1
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• pp.71-84
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• 1983

This study was made to investigate the ultrastructural changes of the hepatocyte of the maternal liver, and fetal liver by Actinomycin D in Wistar rats at the stage of pregnancy. Peritoneal injection of Actinomycin D to rats carried out gestation day 7 to 9 at the level of $15{\mu}g(11.5{\mu}g/100g$ body wt.), $20{\mu}g(15.8{\mu}g/100g$ body wt.) on each day. Treated animals with saline only were used for controls. Animals were sacrificed on day 15 of gestation. On electron microscopic examination, the hepatocytes of maternal liver given Actinomycin D $15{\mu}g$/ml had evidence of serious cellular damage, for example, hypertrophy of rough endoplasmic reticulum, loss in nucleolar osmiophilia, swelling of Golgi apparatus and change of mitochondrial structure. Maternal liver given Actinomycin D $20{\mu}g/ml$ shown similar changes to that of the $15{\mu}g/ml$ treated animals. But mitochondria of this group were not changed than that of $15{\mu}g/ml$ treated group. In the hepatocytes of fetal liver, changes were more pronounced. The drug produced alteration in nuclei and cytoplasm. The rough endoplasmic reticulum was swollen and there were ribosomes detachement. In addition, damages of mitochondria, Golgi apparatus were detected.