• Economic and Environmental Geology
• /
• v.43 no.4
• /
• pp.371-379
• /
• 2010

Fresh water injection test in a fractured bedrock aquifer was applied as an efficient approach to lower saline concentrations in the saltwater-freshwater transition zone formed by seawater intrusion in a coastal area. The methodology and effectiveness of fresh water injection for hydraulically controlling seawater intrusion is overwhelmingly site dependent, and there is an urgent need to characterize the permeable fractures or unconsolidated porous formations which can allow for seawater flow and transport. Considering aquifer characteristics, injection and monitoring boreholes were optimally designed and completed to inject fresh water through sand layer and fractured bedrock, respectively. We devised and used the injection system using double packer for easy field operation and maintenance. Overall fracture distribution was systematically identified from borehole image logs, and the section of fresh water injection was decided from injection test and monitoring. With fresh water injection, the fluid electrical conductivity of the monitoring well started to be lowered by the inflow of fresh water at the specific depth. And this inflow leaded to the replacement of the fluid in the upper parts of the borehole with fresh water. Furthermore, the injection effect lasted more than several months, which means that fresh water injection may contribute to the mitigation of seawater intrusion in a coastal area.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.8
• /
• pp.5534-5540
• /
• 2015

This In the railway signaling system, applications of axle counter in addition to track circuit goes on increasing for detecting train position. Consequently, this paper compares sensor methods of axle counter with between geo-magnetism method and proximity sensor method. And it presents differences and results, to improve reliabilities of train detection and axle counting. Also, this article presents an applied result which is based on field experience, with regard to installation, considering attachment condition of sensor part for accurate axle counting. This study acquires expandability that is able to perform not only axle counting function but also various other functions (direction detection of train, speed detection of train, and so on). It was a result of a change of design in order to judge phase difference of sensors, to improve reliability of axle counting. Furthermore, it does not subordinate to characteristics (type, weight of train). And it is confirmed that the omission of axle counting was not occurred in 350km/h. This was the result of Lab test after the construction of transfer equipment of trial axle and Test Bed for axle counting. Both of them are self-productions. Through this, it prepares foundation which is able to apply not only to train detection but also to speed of passing trains, formation number of trains, detector locking condition - when the train passes the section of switch point, and level crossing devices. Furthermore, it would be judged to contribute safety train operation if proximity sensor method applies to the whole railway signaling system from now on.

• The Journal of the Korea Contents Association
• /
• v.12 no.9
• /
• pp.357-368
• /
• 2012

The purpose of this study is to empirically examine the impact of enterprise R&D investment on international trade in Korea under the new Normal Era. In order to test whether the time series data of trade variables are stationary or not, we put in operation unit root test and cointegration test. Based on VECM (Vector Error Correction Model), we also apply impulse response functions and variance decomposition to estimate the dynamic effects in the short-run and long-run. The results show that the relationship between enterprise R&D investment and international trade (export and import) exists in the long-run as well as in the short-run. The results of applying impulse response functions and variance decomposition also indicate that the impact of enterprise R&D investment on international trade is positive, and a significant portion of fluctuations in the trade variable is explained by enterprise R&D investment. Therefore, enterprise R&D investment must be continuously increased to improve economic growth with promoting trading competition power in Korea under the new Normal Era.

• International Journal of Contents
• /
• v.11 no.2
• /
• pp.37-49
• /
• 2015

Sensors, equipment, ICT facilities and their corresponding software have a relatively short lifetime relative to that of constructional structure, so these devices have to be continuously fixed or exchanged during maintenance and management. Furthermore, software or analysis tools should be periodically upgraded according to advances in ICT and analysis technology. Conventional monitoring systems have serious problems in that it is difficult for site engineers to modify or upgrade hardware and analysis algorithms. Moreover, we depend on the original system developer when we want to modify or upgrade inner program structures. In this paper, we propose a novel design for integrated maintenance and management of a monitoring system by applying the mobile cloud concept. The system is intended for use in disaster prevention of constructional structures, including bridges, tunnels, and in traditional buildings in a local heritage village, we analyze the status of these structures over a long term or a short-term period as well as in disaster situations. Data are collected over a mobile cloud and future expectations are analyzed according to probabilistic and statistical techniques. We implement our integrated monitoring system to solve the existing problems mentioned above. The final goal of this study is to design and implement a monitoring system for more than 10,000 structures spread within Korea. Furthermore, we can specifically apply the monitoring system presented here to a bridge made from timber in Asan Oeam Village and a traditional house in Andong Hahoe Village to monitor for possible disasters. The entire system design and implementation can be developed on the LinkSaaS platform and the monitoring services can also be implemented on the platform. We prove that the proposed system has good performance by performing a TTA authentication test, web accommodation test, and operation test using emulated data.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.51 no.11
• /
• pp.187-192
• /
• 2014

Various researches are performed to extract significant features from continuous images. The FAST algorithm has the simple structure for arithmetic operation and it is easy to extraction the features in real time. For this reason, the FPGA based hardware accelerator is implemented and widely applied for the FAST algorithm. The hardware accelerator needs the threshold to extract the features from images. The threshold is influenced not only the number of extracted features but also the total execution time. Therefore, the way of threshold control is important to stabilize the total execution time and to extract features as much as possible. In order to control the threshold, this paper proposes the PI controller. The function and performance for the proposed PI controller are verified by using test images and the PI control logic is designed based on Xilinx Vertex IV FPGA. The proposed scheme can be implemented by adding 47 Flip Flops, 146 LUTs, and 91 Slices to the FAST hardware accelerator. This proposed approach only occupies 2.1% of Flip Flop, 4.4% of LUTs, and 4.5% of Slices and can be regarded as a small portion of hardware cost.

• Journal of Navigation and Port Research
• /
• v.40 no.3
• /
• pp.159-164
• /
• 2016

The goal of this study is to implement a communication system that can monitor the status of the nacelle using the power cable itself, without the dedicated communication lines such as an UTP cable and optical fiber for the offshore wind turbine. An inductive coupling powerline communication system for a MW class offshore wind turbine was proposed and its communication performance was demonstrated. The inductive couplers was designed for operation at up to 500 A using a ferrite composite materials. Field test was carried out on the wind farms of Jeju island. Using the iperf communication test program, we have obtained more than 15 Mbps data transmission rate through the 100 m power cable that was installed between the nacelle and the bottom of the power converter. In the data transmission stability test for a week, there was no failure ever. The minimum transmission rate was 15 Mbps and the average data rate was about 20 Mbps. Next, we have installed an infrared camera inside the nacelle in order to measure the temperature distribution and variation of the nacelle. The real-time thermal image taken by the camera was successfully sent to the monitoring system without error.

• Journal of Korean Society of Environmental Engineers
• /
• v.35 no.10
• /
• pp.694-702
• /
• 2013

The purpose of this study is to evaluate a de-watering filtrate treatment and the possibility of securing biological treatment capacity by changing the structure of the secondary clarifier. Accordingly, the column test was conducted to determine the effect of polymer in the de-watering filtrate on sludge sedimentation. Also, the characteristics of de-watering filtrate processing was evaluated through batch test and continuous processing operation. The results showed that sludge settling velocity increased with higher polymer concentration, and that effluent SS concentration was found to decrease. Regarding processing characteristics of de-watering filtrate, the removal efficiency of TSS and TBOD5 increased as the length of secondary clarifier was longer. Also, comparing injections into anoxic tank and secondary clarifier, de-watering filtrate by continuous infusion treatment process showed stability in both conditions. Therefore, by modifying the structure of secondary clarifier, efficient processing of de-watering filtrate is expected to be possible and processing capacity of small sewage treatment plants is considered to be improved.

• Journal of Satellite, Information and Communications
• /
• v.6 no.2
• /
• pp.97-101
• /
• 2011

Interplanetary space between Sun and Earth is area of flowing very fast solar wind which is contained X ray, flare, corona mass, etc. occurred Sun surface to Earth. This solar wind is affected directly to Earth magnetosphere and ionosphere so that this bring out broadcasting and communication interruptions, satellite operation obstacles and power gird defects and etc..Solar wind flow in interplanetary space is measured as solar wind speed, density and direction by measuring scintillation value to be produced during radio source is passed through solar wind. The wider effective collective areas and the more radio sources, accuracy of solar wind measuring is got higher. Function test was performed using 3 tiles which was manufactured as prototype. Restriction of quantity of tiles, test was performed to confirm whether measured beam pattern is complied with requirement or not. In this paper, it is shown design and their specification of ground interplanetary radio measurement system as well as technical issues and resolutions which were raised during design phase. Also result of function verification test using prototype is suggested. It is confirmed that measured beam pattern was met with requirement.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.24 no.2
• /
• pp.295-310
• /
• 2014

DCS (Distributed Control System), the main control system of power plants, is an automated system for enhancing operational efficiency by monitoring, tuning and real-time operation. DCS is becoming more intelligent and open systems as Information technology are evolving. In addition, there are a large amount of investment to enable proactive facility management, maintenance and risk management through the predictive diagnostics. However, new upcoming weaponized malware, such as Stuxnet designed for disrupting industrial control system(ICS), become new threat to the main control system of the power plant. Even though these systems are not connected with any other outside network. The main control systems used in the power plant usually have been used for more than 10 years. Also, this system requires the extremely high availability (rapid recovery and low failure frequency). Therefore, installing updates including security patches is not easy. Even more, in some cases, installing security updates can break the warranty by the vendor's policy. If DCS is exposed a potential vulnerability, serious concerns are to be expected. In this paper, we conduct the penetration test by using NESSUS, a general-purpose vulnerability scanner under the simulated environment configured with the Ovation version 1.5. From this result, we suggest a log analysis method to detect the security infringement and react the incident effectively.

• Korean Journal of Clinical Laboratory Science
• /
• v.44 no.2
• /
• pp.66-74
• /
• 2012

Test turnaround time (TAT) is the lead time from reception to reporting. In the complete blood cell count (CBC), 4 units of the XE-2100 (Sysmex Corp., Japan) processed around 80% of quantity, 1 unit of the LH-780 (Beckman-Coulter Incorp., USA) processed around 10% and 1 unit of ADVIA-2120 (Siemens AG, Munich, Germany) processed around 10%. We analyzed the change in the TAT for the CBC for over 7 years, from January of 2005 to December of 2011. The delta check made alterations of delta to WBC, hemoglobin, hematocrit, platelet and metamyelocyte, however, did not made them to band neutrophil, eosinophil, basophil and monocyte. The panic value check made alterations of panic value to hemoglobin, hematocrit, platelet and monocyte. In the criteria of currently slide review, LH-780 and ADVI-2120 analyzers prepared suspect flags of "Blast, Imm NE2, Immature granulocyte, Imm NE1, Left shift, Variant lymphocyte, Atypical lymphocyte, Platelet clumps and NRBC". The New slide review in the XE-2100 analyzer altered the preparations of a smear slide more than a "Platelet clumps flag(${\geq}200unit$), a single flag excluding the "Platelet clumps flag (${\geq}250unit$) and a multiple flag (${\geq}200unit$)". Also, below the 240 unit, medical technologists prepared manual slides selectively according to their evaluations. The automatic reporting rate was 33.4% without alterations, whereas it was 41.0% without alterations, and was thus improved by 7.6%. The slide review rate was 15.2% before using the Q-flag limit, whereas it was 12.1% for a reduce 3.1%. TAT was 45 minutes without the creation alterations of the delta and panic value checks, whereas it was 35 minutes after making alterations of the delta and panic value checks and thus was shortened by 10 minutes. We came to the conclusion that the establishment and operation of delta and panic value checks and slide review criteria suitable for laboratory environment can reduce unnecessary smear slides, re-checking, re-sampling, re-testing, telephone inquiries and concentrated workloads during specific times of the day.