• KIPS Transactions on Computer and Communication Systems
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• v.10 no.11
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• pp.297-304
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• 2021

Commercial obfuscation tools (protectors) aim to create difficulties in analyzing the operation process of software by applying obfuscation techniques and Anti-reversing techniques that delay and interrupt the analysis of programs in software reverse engineering process. In particular, in case of virtualization detection and anti-debugging functions, the analysis tool exits the normal execution flow and terminates the program. In this paper, we analyze Anti-reversing techniques of executables with Debugger Detection and Viralization Tools Detection options through VMProtect 3.5.0, one of the commercial obfuscation tools (protector), and address bypass methods using Pin. In addition, we predicted the location of the applied obfuscation technique by finding out a specific program termination routine through API analysis since there is a problem that the program is terminated by the Anti-VM technology and the Anti-DBI technology and drew up the algorithm flowchart for bypassing the Anti-reversing techniques. Considering compatibility problems and changes in techniques from differences in versions of the software used in experiment, it was confirmed that the bypass was successful by writing the pin automation bypass code in the latest version of the software (VMProtect, Windows, Pin) and conducting the experiment. By improving the proposed analysis method, it is possible to analyze the Anti-reversing method of the obfuscation tool for which the method is not presented so far and find a bypass method.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.2
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• pp.210-215
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• 2017

We have developed the neuromorphic system that can work with the four-terminal Si-based synaptic devices and verified the operation of the system using simulation tool and printed-circuit-board (PCB). The symmetrical current mirrors connected to the n-channel and p-channel synaptic devices constitute the synaptic integration part to express the excitation and the inhibition mechanism of neurons, respectively. The number and the weight of the synaptic devices affect the amount of the current reproduced from the current mirror. The double-stage inverters controlling delay time and the NMOS with large threshold voltage ($V_T$) constitute the action-potential generation part. The generated action-potential is transmitted to next neuron and simultaneously returned to the back gate of the synaptic device for changing its weight based on spike-timing-dependent-plasticity (STDP).

• Journal of Korea Water Resources Association
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• v.50 no.1
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• pp.65-73
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• 2017

This study analyzed the peak drought severity and drought duration of the Cheongmicheon watershed from 1985 to 2015 to assess the lag time of peak drought severity between several drought indices. Standardized Precipitation Index (SPI) based on precipitation and Standardized Precipitation Evapotranspiration Index (SPEI) based on precipitation and evapotranspiration were applied as meteorological drought indices. Streamflow Drought Index (SDI) based on runoff data was applied as hydrological drought index. In case of SDI, we used Soil and Water Assessment Tool (SWAT) model for simulation of daily runoff data. As a result, the time of peak drought severity of SDI occurred after the occurrence of SPI and SPEI. The lag time for the peak drought severity, on average, between SDI and SPI was 0.59 months while SDI and SPEI was 0.79 months. As compared with SDI, the maximum delay was 2 months for both SPI and SPEI. This study results also shows that even though the rainfall events were able to cope with meteorological droughts, they were not always available to solve the hydrological droughts in the same time.

• The Journal of Internal Korean Medicine
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• v.36 no.3
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• pp.276-283
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• 2015

Objectives: The purpose of this study is to report bowel sound patterns recorded in 3 diseases associated with structural deformity of the pylorus-duodenum. Methods: : Bowel sound recording is a useful non-invasive tool for the evaluation of gastrointestinal motility. However, the difficulty in manual attachment of the electronic stethoscope on the abdominal wall and noise production against bowel sound signals have prohibited its widespread use. Therefore, I developed a new apparatus that eliminates the noise; it contains a sound absorbing device and a holder for the head of stethoscope. Using the new bowel sound recording system, bowel sounds of the patients were recorded repeatedly. The endoscopic and abdominal computed tomography findings were obtained from other hospitals' medical record, and all patients were confirmed to have structural deformity in the pylorus-duodenum. The records of each patient were compared and assessed. Results: : Patients had either duodenal ulcer scar, pyloric stricture, or far advanced malignant stomach cancer, as diagnosed by the gastroscopy. Their dominant frequency of bowel sound obtained from the new system was checked more than 2 times at regular intervals. All 8 recordings in the 2 patients with duodenal ulcer scar (5 times) or pyloric stricture (3 times) showed a decrease in postprandial than fasting dominant frequency. One patient with stomach cancer showed no significant change between postprandial and fasting states at 2 recordings. Conclusions: The analysis of dominant frequency in bowel sounds can indicate the existence of pyloric obstruction that could delay gastric emptying.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.228.2-228.2
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• 2015

We have developed a TOF-MEIS system using 70~100 keV He+. A TOF-MEIS system was designed and constructed to minimize the ion beam damage effect by utilizing a pulsed ion beam with a pulse width < 1 ns and a TOF delay-line-detector with an 120 mm diameter and a time resolution of 180 ps. The TOF-MEIS is an useful tool for interfacial analysis of the composition and structure of nano and bio systems. Our recent applications are reported. We investigated the effect with Polyaspartic Acid (pAsp) and Osteocalcin on the initial bone growth of calcium hydroxyl appatite on a carboxyl terminated surface. When pAsp is not added to the self-assembled monolayers of Ca 2mM with Phosphate 1.2 mM, the growth procedure of calcium hydroxyl appatite cannot be monitored due to its rapid growth. When pAsp is added to the SAMs, the initial grow stage of the Ca-P can be monitored so that the chemical composition and their nucleus size can be analyzed. Firstly discovered the existence of 1-nm-sized abnormal calcium-rich clusters (Ca/P ~ 3) comprised of three calcium ions and one phosphate ion. First-principles studies demonstrated that the clusters can be stabilized through the passivation of the non-collagenous-protein mimicking carboxyl-ligands, and it progressively changes their compositional ratio toward that of a bulk phase (Ca/P~1.67) with a concurrent increase in their size to ~2 nm. Moreover, we found that the stoichiometry of the clusters and their growth behavior can be directed by the surrounding proteins, such as osteocalcin.

• Journal of Korean Society on Water Environment
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• v.28 no.4
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• pp.595-600
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• 2012

This study is to assess the application of SWAT-CUP(Soil and Water Assessment Tool-Calibration Uncertainty Programs) and to extend daily flow data from 8-day interval flow data which has been measured by Korean Ministry of Environment(MOE). Model sensitivity analysis and calibration were performed with sequential uncertainty fitting(SUIF-2), which is one of the programs interfaced with SWAT, in the package SWAT-CUP. The most sensitive parameters were SOL_K.sol, CH_N2.rte, CN2.mgt, SOL_BD.sol, ALPHA_BF.gw, ALPHA_BNK.rte, SOL_AWC.sol, CH_K2.rte, SFTMP.bsn, GW_DELAY.gw. Following the sensitivity analysis, SWAT-CUP calibration was carried out using 8-day interval flow data from January 2008 to December 2010. The results were then assessed based on the visual agreement and simulated flow plots and the performance statistics generated $R^2$ and NSE which are 0.71 and 0.61 respectively. Results of these statistics indicated that there was a good agreement between the observed and simulated flow. To extend daily flow data from 8-day interval flow data, parameters, which were estimated by SWAT-CUP, re-entered for SWAT model. As a result, the observed flow data were found to reflect the trend of simulated flow data. From these results, it is thought that this method could be used to provide daily flow data using 8-day interval flow data.

• The KIPS Transactions:PartC
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• v.8C no.1
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• pp.97-104
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• 2001

In this paper, we present a new hierarchical model for performance analysis of channel allocation and packet service protocol in wireless n network. The proposed hierarchical model consists of two parts : upper and lower layer models. The upper layer model is the structure state model representing the state of the channel allocation and call service. The lower layer model, which captures the performance of the system within a given structure state, is the wireless packet retransmission protocol model. These models are developed using SRN which is an modeling tool. SRN, an extension of stochastic Petri net, provides compact modeling facilities for system analysis. To get the performance index, appropriate reward rates are assigned to its SRN. Fixed point iteration is used to determine the model parameters that are not available directly as input. That is, the call service time of the upper model can be obtained by packet delay in the lower model, and the packet generation rates of the lower model come from call generation rates of the upper model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3390-3397
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• 2010

The purpose of this study was to evaluate the validity and utility of the Korean-Ages and Stages Questionnaires(K-ASQ) as a screening tool for detecting developmental delay of preschool child in community. Informed consents from parents of 229 children were received for the process of the study. The subjects were 229 parents and the children of three to five years old who did not have reported genetic diseases or developmental delays. The result of this study, validity were calculated for the K-ASQ sensitivity 0.41%, specificity 0.76%, hyper-referral 0.14%, hypo-referral 0.21%. Predictive value of delayed development were K-ASQ 0.70% and that of normal development were K-ASQ 0.77%. K-ASQ can be feasibly used in the setting of health clinic and be the highly predictive criteria for delayed development and normal development.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.2
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• pp.239-249
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• 2003

A lot many WWW sites are come into the world more and more as Web is considered as the unified Internet information tool. The location of each site or resource is usually specified by a physical URL, which is often too long to remember and tends to raise difficulty to show the aim of the site intuitively by seeing it. Since any person or organization can get his/her own domain name easily, it is more desirable to use a logical URL with the domain name which can be chosen more compact to remember and meaningful to represent the ultimate intention of the site. This paper presents an implementation of a URL forwarding server which forwards a URL to another, so that a WWW site can use a logical URL instead of a physical one. The server consists of a domain mapper which uses the redirection transaction of the HTTP protocol, and a name server based on the HIND. The paper shows how the interaction between the domain mapper and the name sever can make forwarding possible and describes its implementation in detail. Experimental results shows that the overhead incurred by URL forwarding is negligible compared to the typical delay of current Internet traffic condition.

• The KIPS Transactions:PartC
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• v.18C no.1
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• pp.15-22
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• 2011

Usually time synchronization is performed after routing tree is constructed. This thesis proposes a time synchronization algorithm combined with single-flooding routing tree construction algorithm in a single path. TSRA (Time Synchronization Routing Algorithm) uses routing packets to construct a routing tree. Two types of time information are added to the routing packet: one is the packet receiving time, and the other is the packet sending time. Time offset and transmission time-delay between parent node and child node could be retrieved from the added time information using LTS (Lightweight Time Synchronization) algorithm. Then parent node sends the time offset and transmission time to children nodes and children nodes can synchronize their time to the parent node time along the routing tree. The performance of proposed algorithm is compared to the TPSN (Timing-sync Protocol for Sensor Networks) which is known to have high accuracy using NS2 simulation tool. The simulation result shows that the accuracy of time synchronization is comparable to TPSN, the synchronization time of all sensor nodes is faster than TPSN, and the energy consumption is less than TPSN.