• Korean Journal of Remote Sensing
• /
• v.33 no.4
• /
• pp.445-454
• /
• 2017

The performance of spatial downscaling models depends on the quality of input coarse scale products. Thus, the impact of intrinsic errors contained in coarse scale satellite products on predictive performance should be properly assessed in parallel with the development of advanced downscaling models. Such an assessment is the main objective of this paper. Based on a synthetic satellite precipitation product at a coarse scale generated from rain gauge data, two synthetic precipitation products with different amounts of error were generated and used as inputs for spatial downscaling. Geographically weighted regression, which typically has very high explanatory power, was selected as the trend component estimation model, and area-to-point kriging was applied for residual correction in the spatial downscaling experiment. When errors in the coarse scale product were greater, the trend component estimates were much more susceptible to errors. But residual correction could reduce the impact of the erroneous trend component estimates, which improved the predictive performance. However, residual correction could not improve predictive performance significantly when substantial errors were contained in the input coarse scale data. Therefore, the development of advanced spatial downscaling models should be focused on correction of intrinsic errors in the coarse scale satellite product if a priori error information could be available, rather than on the application of advanced regression models with high explanatory power.

• The KIPS Transactions:PartA
• /
• v.12A no.5 s.95
• /
• pp.427-432
• /
• 2005

I studied about existent load distribution algorithms and the WLC(Weighted Least Connection) algerian that is using much at present to distribute the connection request of users to real servers efficiently in web cluster system. The efficiency of web cluster system is fallen by load imbalance between servers, because there is problem In inaccurate load status measuring of servers and measuring timing at these load distribution algorithms. In this paper, I suggest an algorithm that distributes load base on various load state of servers by real time using broadcasting RPC(Remote Procedure Call) when a user requests connection, and implement a prototype and experiment its performance. The experiment result shows that load imbalance phenomenon between reai sowers was improved greatly than existing method, and performance of web cluster system was improved by efficiency that response time is shortened.

• Korean Journal of Remote Sensing
• /
• v.22 no.4
• /
• pp.255-264
• /
• 2006

GRACE (Gravity Recovery and Climate Experiment) is the first dedicated gravity mapping mission. Its primary measurements are the distance changes between two co-orbiting low earth satellites. GRACE is a joint development by NASA and German DLR and was launched in March 2002. GRACE improves the Earth gravity model accuracy by nearly two factor of magnitude over pre-launch models. After brief description of the GRACE primary instrument, inter-satellite ranging system, its flight status and preliminary performance evaluation is presented. Ranging system error models, which were not included in the pre-launch performance model and design specifications, are identified through analyzing the flight data. Base on this analysis, future research topics on the GRACE instrument performance analysis are discussed.

• Korean Journal of Remote Sensing
• /
• v.12 no.1
• /
• pp.26-42
• /
• 1996

The CCD Earth Images Experiment(CEIE) is one of the main payload of the KITSAT-1. Since it was launched on Oct. 10, 1992, the CEIE has taken more than 500 images on the Earth surface world-wide so far. An image from the space is very different from a feature on the real Earth surface due to various radiometric and geometric distortions. Preprocessing to remove those distortions has to take place before the images data are processed and analyzed further for various applications. This paper describes the procedure to perform preprocessing including radiometric and geometric correction.e-processing system. The GCP marking using this technique showed a sufficient accuracy for KITSAT1,2 narrow camera images.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.36 no.6
• /
• pp.483-489
• /
• 2016

The typical methods used for inspecting ferromagnetic pipes include the ultrasonic testing (UT) contact method and the following non-contact methods: magnetic flux leakage (MFL), electromagnetic acoustic transducers (EMAT), and remote field eddy current testing (RFECT). Among these methods, the RFECT method has the advantage of being able to establish a system smaller than the diameter of a pipe. However, the method has several disadvantages as well, including different sensitivities and difficult-to-repair coil sensors which comprise its array system. Therefore, a giant magneto-resistance (GMR) sensor was applied to address these issues. The GMR sensor is small, easy to replace, and has uniform sensitivity. In this experiment, the GMR sensor was used to measure remote field and defect signal characteristics (in the axial and radial directions) in a ferromagnetic pipe. These characteristics were measured in an effort to investigate standard defects at changing depths within a pipe. The results show that the experiment successfully demonstrated the applicability of the GMR sensor to RFECT signal detection in ferromagnetic pipe.

• Journal of the Korean Society of Radiology
• /
• v.15 no.6
• /
• pp.795-801
• /
• 2021

The designed drone-based unmanned remote radiation detection module was developed according to the needs of the nuclear power plant decommissioning workshop. Using the Geiger-Mueller tube sensitive to low-level radiation measurement, It was manufactured to measure the amount of radiation leaking into and out of the containment vessel. The drone-based radiation detection module weighs less than 200g, It can be operated inside and outside the containment vessel of a nuclear power plant. To check the performance of the designed equipment, a performance evaluation test was conducted with reference to the international standard (IEC-60864). The stability of the radiation detection module designed to meet the needs of the field the statistical rate of change by repeated measurements in the rate of change experiment to evaluate the measurement accuracy was ±4.6%. The accuracy ±7.3% in the linearity experiment to evaluate the dose rate dependence, the linear The figure satisfies the international performance evaluation standard of ±3.5%. The radiation detection module developed in this study is a customized equipment for a nuclear power plant dismantling workshop. It will be helpful for accurate measurement of space dose rate and safety management of radiation worksites in sites with a lot of radiation dust.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.14 no.2
• /
• pp.303-308
• /
• 2019

Spring framework is widely used as a base technology for e-government frameworks and to the extent it is a standard for web service development tools of Korean public institutions. However, recently, a remote code execution vulnerability(CVE-2018-1270) was found in an application using a spring framework. This paper proposes a method of analyzing the vulnerability experiment using a hacking scenario, Proof Of Concept(POC), in which the spring framework is a hazard to the server. We propose the patch to version 4.3.16 and version 5.0.5 or later as an ultimate response. It is also expected that the proposed experiment analysis on vulnerability of hacking scenario will be used as a data for improving performance of security programs and establishing a new authentication system.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.75-75
• /
• 2022

Traditional agriculture mostly focused on activity in the field, but current agriculture faces problems such as reduction of agricultural inputs, labor shortage and so on. Accordingly, traditional agricultural experiments generally considered the simple treatment effects, but current agricultural experiments need to consider the several and complicate treatment effects. To analyze such several and complicate treatment effects, data collection has the first priority. Remote sensing is a quite effective tool to collect information in agriculture, and recent easier availability of UAVs (Unmanned Aerial Vehicles) enhances the effectiveness. LAI (Leaf Area Index) is one of the most important information for evaluating the condition of crop growth. In this study, we utilized UAV with multispectral camera to evaluate plant-based LAI of sweetcorn in a small-scale field experiment and discussed the feasibility of a new experimental design to analyze the several and complicate treatment effects. The plant-based SR measured by UAV showed the highest correlation coefficient with LAI measured by a canopy analyzer in 2018 and 2019. Application of linear mix model showed that plant-based SR data had higher detection power due to its huge number of data although SR was inferior to evaluate LAI than the canopy analyzer. The distribution of plant-based data also statistically revealed the border effect in treatment plots in the traditional experimental design. These results suggest that remote sensing with UAVs has the advantage even in a small-scale experimental plot and has a possibility to provide a new experimental design if combined with various analytical applications such as plant size, shape, and color.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2008.05a
• /
• pp.841-844
• /
• 2008

This paper describes technical method about remote control and monitoring of local system by use internet web connection system, which connect local system and system manager works in long distance office. The local system, which will be controlled remotely have constructed with analog/digital signal acquisition device, signal control board and their software. The local systems are constructed with several electronic modules need AC or DC power supply to operate the right way. We used NI labview software to control and monitoring of local system. The computer server for remote connection are constructed with Apache web server, PHP and MySQL ODBC. The experiment for the remote control are need internet web browser which load local control software. By use of web system, we have experimented control and monitoring of local electronic module.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.9 no.5
• /
• pp.1184-1192
• /
• 2008

There have been a large number of trials of the experimental education in engineering using virtual laboratories implemented in virtual space, namely on the Web. Although virtual education is regarded as an effective educational means that overcomes the limit of time and space and bring high teaming effects, the problem of lack of reality must be solved. The present study proposed and implemented a real-time remote laboratory as a solution for the problem of lack of reality in virtual education. The remote laboratory provides functions with which learners can perform experiments by remote-controlling circuits and equipment related to experiments and practices on the Web and gets data and image information, so through it learners can make realistic experiments at any time and in any place. The remote laboratory module based on Internet open sources such as JAVA Web start technology, FTP technology and Telnet technology in server-client environment can be implemented at low cost, and is effectively applicable to engineering experiment education in various areas related to real-time hardware control.