• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.5
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• pp.521-526
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• 2014

In this study, closed-cell aluminum foam with an initial crack was investigated to produce an axial load-time graph. Using the 10-kN Landmarks of MTS Corporation, a 15-mm/min velocity of mode I shape was applied to the aluminum foam specimen using the displacement control method. ABAQUS 6.10 simulation was used to model and analyze the identical model in three dimensions under conditions identical to those of the experiment. The energy release rate was calculated on the basis of an axial load-displacement graph obtained from the experiment and a transient image of the crack length, and then an FE model was analyzed on the basis of this fracture energy condition. The relation between load and displacement was discussed; it was found that the aluminum foam deformed somewhat less than the adhesive layer owing to the difference in elastic modulus.

• Journal of Astronomy and Space Sciences
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• v.39 no.1
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• pp.1-10
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• 2022

The universe is thought to be filled with not only Standard Model (SM) matters but also dark matters. Dark matter is thought to play a major role in its construction. However, the identity of dark matter is as yet unknown, with various search methods from astrophysical observartion to particle collider experiments. Because of the cross-section that is a thousand times smaller than SM particles, dark matter research requires a large amount of data processing. Therefore, optimization and parallelization in High Performance Computing is required. Dark matter in hypothetical hidden sector is though to be connected to dark photons which carries forces similar to photons in electromagnetism. In the recent analysis, it was studied using the decays of a dark photon at collider experiments. Based on this, we studies double dark photon decays at lepton colliders. The signal channels are e⁺e^- → A'A' and e⁺e^- → A'A'γ where dark photon A' decays dimuon. These signal channels are based on the theory that dark photons only decay into heavily charged leptons, which can explain the muon magnetic momentum anomaly. We scanned the cross-section according to the dark photon mass in experiments. MadGraph5 was used to generate events based on a simplified model. Additionally, to get the maximum expected number of events for the double dark photon channel, the detector efficiency for several center of mass (CM) energy were studied using Delphes and MadAnalysis5 for performance comparison. The results of this study will contribute to the search for double dark photon channels at lepton colliders.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10a
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• pp.287-289
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• 1999

다등급 보안 자료기지 관리체계는 하위 등급의 자료에 대한 쓰기 연산 및 상위 등급의 자료에 대한 읽기 연산을 불허하여, 상위 등급의 자료가 하위 등급의 거래에 노출되는 것을 방지한다. 하지만, 전통적인 다등급 보안 자료기지 관리체계는 서로 상이한 등급간 거래의 공모로 생성될 수 있는 비밀 경로는 차단할 수 없다. 이러한 비밀 경로의 생성을 막기 위한 여러 연구가 다중 버전의 환경 및 제한된 버전의 환경 하에서 수행되어 왔다. 하지만 다중 버전에 기반한 기법은 상위 등급의 거래가 지나치게 오래된 버전의 자료를 읽을 뿐 아니라 버전 관리를 위하여 추가적인 부담이 요구된다는 단점이 있고, 제한된 버전에 기반한 기법은 항상 상위 등급 거래의 지연 및 철회를 강요한다는 단점이 있다. 본 논문에서는 제한된 버전 하에서 직렬화 가능성 그래프 검사 기법을 사용하여, 각 보안 등급간의 형평성을 높일 수 있는 비밀경로 생성 방지 기법을 제안한다.

• Korean Journal of Food Science and Technology
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• v.29 no.6
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• pp.1131-1137
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• 1997

The production rates of leavening gases and textures of cookies were investigated with various chemical leavening agents(baking powders). The chemical leavening agents could be divided into three group of a fast-acting group such as potassium bicarbonate, tartaric acid, aluminium ammonium sulfate, and fumaric acid, a slow-acting group such as ammonium bicarbonate, sodium bicarbonate, $glucono-{\delta}-lactone$, and ammonium chloride. and a double-acting group such as anhydro monocalcium phosphate, disodium dihydrogenpyrophosphate, and aluminium potassium sulfate according to the different production rate of gases. The leavening rate of ammonium bicarbonate, which was the highest of all leavening agents used in this experiment, was 131.25%. But its after-taste in a cookie was not good due to the residual ammonia. $Glucono-{\delta}-lactone$ only had no after-taste. The higher leavening rate, the more peaks in texture profile graph. Ammonium bicarbonate showed the most peaks in this experiment. It was found that the number of peak had correlation with brittleness of cookies $(r^2=0.8176)$ and brittleness of cookies was different as to various chemical leavening agents.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.1
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• pp.44-49
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• 2022

In this paper, we investigated current (I)- and voltage (V)-sweeping properties in a double-stack structure, Ge₂Sb₂Te₅/Ti/W-doped Ge₈Sb₂Te₁₁, a candidate medium for applications to multilevel phase-change memory. 200-nm-thick and W-doped Ge₂Sb₂Te₅ and W-doped Ge₈Sb₂Te₁₁ films were deposited on p-type Si(100) substrate using magnetron sputtering system, and the sheet resistance was measured using 4 point-probe method. The sheet resistance of amorphous-phase W-doped Ge₈Sb₂Te₁₁ film was about 1 order larger than that of Ge₂Sb₂Te₅ film. The I- and V-sweeping properties were measured using sourcemeter, pulse generator, and digital multimeter. The speed of amorphous-to-multilevel crystallization was evaluated from a graph of resistance vs. pulse duration (t) at a fixed applied voltage (12 V). All the double-stack cells exhibited a two-step phase change process with the multilevel memory states of high-middle-low resistance (HR-MR-LR). In particular, the stable MR state is required to guarantee the reliability of the multilevel phase-change memory. For the Ge₂Sb₂Te₅ (150 nm)/Ti (20 nm)/W-Ge₈Sb₂Te₁₁ (50 nm), the phase transformations of HR→MR and MR→LR were observed at t<30ns and t<65ns, respectively. We believe that a high speed and stable multilevel phase-change memory can be optimized by the double-stack structure of proper Ge-Sb-Te films separated by a barrier metal (Ti).

• Korean Journal of Applied Biomechanics
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• v.14 no.3
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• pp.17-35
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• 2004

The purpose of this study is to explain developmental process of gait via angle-angle diagram to understand how coordinated relationships and control change with age. Twenty four female children, from one to five years of age were the test subjects for this study, and their results were compared to a control group consisting of twenty one adult females. The Vicon 370 CCD camera, VCR, video timer, monitor, and audio visual mixer was utilized to graph the gait cycle for all test subjects. Both coordinated Intra-limb relationships, and range of motion and timing according to quadrant were explained through the angle angle diagram. Movement in the sagittal plane showed both coordinated relationships and control earlier than movement in the coronal or transverse plane. In the sagittal plane, hip and Knee coordinated relationships developed first (from one year of age.) Coordinated relationships in the Knee and ankle and hip and ankle developed next, respectively. Both hip and ankle and knee and ankle development were inhibited by the inability of children to completely perform plantar flexion during the swing and initial double limb support phases. Children appeared to compensate for this by extending at their hip joint more than adults during the third phase, final double limb support. In many cases the angle angle diagram for children had a similar shape as adult's angle angle diagram. This shows that children can coordinate their movements at an early age. However, the magnitudes and timing of children's angle angle diagrams still varied greatly from adults, even at five years of age. This indicates that even at this age, children still do not possess full control of their movements.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.6
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• pp.2781-2800
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• 2016

Emerging attacks aim to access proprietary assets and steal data for business or political motives, such as Operation Aurora and Operation Shady RAT. Skilled Intruders would likely remove their traces on targeted hosts, but their network movements, which are continuously recorded by network devices, cannot be easily eliminated by themselves. However, without complete knowledge about both inbound/outbound and internal traffic, it is difficult for security team to unveil hidden traces of intruders. In this paper, we propose an autonomous anomaly detection system based on behavior profiling and relation mining. The single-hop access profiling model employ a novel linear grouping algorithm PSOLGA to create behavior profiles for each individual server application discovered automatically in historical flow analysis. Besides that, the double-hop access relation model utilizes in-memory graph to mine time-sequenced access relations between different server applications. Using the behavior profiles and relation rules, this approach is able to detect possible anomalies and violations in real-time detection. Finally, the experimental results demonstrate that the designed models are promising in terms of accuracy and computational efficiency.

• Journal of KIISE:Information Networking
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• v.28 no.4
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• pp.657-664
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• 2001

In our predecessor paper(Part I)[13], we introduced a graph that represents the crosstalk relationship among multicast connections in the photonic Banyan-type switching network, and found the upper bound on the degree of it. In this paper(Part II), we consider the number of routing rounds(i.e., scheduling length) required for SE(switching element)-disjoint multicasting in photonic Banyan-type switching networks. Unfortunately, the problem to find an optimal scheduling length is NP-complete thus, we propose an approximation algorithm that gives its scheduling length is always within double of the upper bound on the optimal length. We also study the scheduling length on the Iink-disjoint(i.e., nonblocking) multicasting. Various nonblocking Banyan-type multicasting networks are found under the scheduling lengths.

• Nuclear Engineering and Technology
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• v.13 no.4
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• pp.207-220
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• 1981

The Np-237 fission cross-sections up to 20 MeV incident neutron energy are calculated by means of the computer code STAPRE- a statistical model code with consideration of preequilibrium decay. The higher chance fissions up to third compound nucleus are taken into account, and the main input parameters in the treatment of fission under consideration of a double-humped fission barrier are carefully adjusted, so that the current trend of experimental data can be fitted within an apparent deviation of about 10% throughout the entire energy range. Results are presented in the form of point-wise cross-section values, and also in the form of graph to demonstrate the shape agreement.

• Journal of Digital Convergence
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• v.10 no.10
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• pp.529-538
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• 2012

This study analyzed a variety of different kinds of usage patterns of four-digit personal identification numbers(PINs) based on the data collected from students attending at A-university in 2011. According to the analysis, the 4 digit PINs '1234' was being used most frequently which is similar to the findings of the study by the Daniel Amitay research. In addition, almost 50 percent of the students were using the four-digit PINs closely related to their personal information, and more than 10 percent of them were using it only by the reason of easiness to remember or convenience to use. Number '0' was the most frequently used, and girl students used it more than boys did. According to the result of analysis of four-digit PINs, it was found that number '1' was the most frequently used in the first and the third position. It was also found that number '2' and number '4' were the most frequently used in the second and the forth position respectively. Among students who had used number 3 in third position, around 63.6 percent of those students were using number 4 in the forth position in their PINs which showed highest frequency from analysis of double-digits connected together in each position. The analysis of PINs were represented by the polygonal (type) graph with that X-axis showed from first to forth position and Y-axis showed number had been used at each position. Among many polygonal graphs, the form showed an N-type which was called in type 1 took the first place by 35 percent.