• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.2
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• pp.301-314
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• 2015

Aiming at accurately distinguishing modeless component and natural vibration mode terms from data series of nonlinear and non-stationary processes, such as Vortex-Induced Vibration (VIV), a new empirical mode decomposition method has been developed in this paper. The key innovation related to this technique concerns the method to decompose modeless component from non-stationary process, characterized by a predetermined 'maximum intrinsic time window' and cubic spline. The introduction of conceptual modeless component eliminates the requirement of using spurious harmonics to represent nonlinear and non-stationary signals and then makes subsequent modal identification more accurate and meaningful. It neither slacks the vibration power of natural modes nor aggrandizes spurious energy of modeless component. The scale of the maximum intrinsic time window has been well designed, avoiding energy aliasing in data processing. Finally, it has been applied to analyze data series of vortex-induced vibration processes. Taking advantage of this newly introduced empirical decomposition method and mode identification technique, the vibration analysis about vortex-induced vibration becomes more meaningful.

• Journal of Aerospace System Engineering
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• v.11 no.6
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• pp.76-83
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• 2017

The MIL-STD-1553 standard has been used for over 40 years as a data bus technology for high-reliability mobile systems. However, 1 Mbps transmission speed is absolutely insufficient to implement sensor data convergence, which is an essential requirement of modern aerospace systems. In this paper, we analyze the hierarchical structure of the MIL-STD-1553B version specification and describe several methods to increase the transmission speed without losing the advantages of the existing MIL-STD-1553 bus. In addition, we analyzed the R & D cases of the high-speed MIL-STD-1553 technology, which have been conducted in leading aerospace countries.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.3
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• pp.500-507
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• 1989

The improvement of volumetric efficiency of air charging into combustion chamber is a primary requirement to obtain better mean effective pressure of an engine. Since parameters such as the air resistances in intake and exhaust flow passages, valve lift and valve timing influence greatly to the volumetric efficiency, it is very convenient and time saving if we can optimize these parameters by computation before we enter into long time fact finding engine tests. In this study we have developed a semi-empirical engine simulation program for the determinations of intake and exhaust valve timings, valve lifts, intake and exhaust port diameters in order to obtain highest volumetric efficiency. In this computation it requires only the measured variational pressures in intake and exhaust port. Using these variational pressures as an input data for our simulation program, we can calculate volumetric efficiency more accurately and can save computing time drastically. To confirm the validity of our simulation program we have made engine operation test in parallel and taken the experimental data. Comparing the computation result with the experimental data obtained through real engine test it has shown only the difference of 3%.

• Smart Structures and Systems
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• v.4 no.6
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• pp.795-807
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• 2008

A challenging problem in structural damage detection based on vibration data is the requirement of a large number of sensors and the numerical difficulty in obtaining reasonably accurate results when the system is large. To address this issue, the substructure identification approach may be used. Due to practical limitations, the response data are not available at all degrees of freedom of the structure and the external excitations may not be measured (or available). In this paper, an adaptive damage tracking technique, referred to as the sequential nonlinear least-square estimation with unknown inputs and unknown outputs (SNLSE-UI-UO) and the sub-structure approach are used to identify damages at critical locations (hot spots) of the complex structure. In our approach, only a limited number of response data are needed and the external excitations may not be measured, thus significantly reducing the number of sensors required and the corresponding computational efforts. The accuracy of the proposed approach is illustrated using a long-span truss with finite-element formulation and an 8-story nonlinear base-isolated building. Simulation results demonstrate that the proposed approach is capable of tracking the local structural damages without the global information of the entire structure, and it is suitable for local structural health monitoring.

• Proceedings of the Korean Magnetic Resonance Society Conference
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• 2002.08a
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• pp.90-90
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• 2002

Syndecans, transmembrane heparan sulfate proteoglycans, are coreceptors with integrin in cell adhesion process. It forms a ternary signaling complex with protein kinase C and phosphatidylinositol 4,5 bisphosphate (PIP2) for integrin signaling. NMR data indicates that cytoplasmic domain of syndecan-4 (4L) undergoes a conformational transition in the presence of PIP2, forming oligomeric conformation. The structure based on NMR data demonstrated that syndecan-4L itself forms a compact intertwined symmetric dimer with an unusual clamp shape for residues Leu$^{186}$ -Ala$^{195}$ . The molecular surface of the syndecan-4L dimer is highly positively charged. In addition, no inter-subunit NOEs in membrane proximal amino acid resides (Cl region) has been observed, demonstrating that the Cl region is mostly unstructured in syndecan-4L dimmer. However, the complex structure in the presence of PIP2 induced a high order multimeric conformation in solution. In addition, phosphorylation of cytoplasmic domain induces conformational change of syndecan-4, resulting inhibition of PKC signaling. The NMR structural data strongly suggest that PIP2 promotes oligomerization of syndecan-4 cytoplasmic domain for PKC activation and further induces structural reorganization of syndecan for mediating signaling network in cell adhesion procedure.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.713-716
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• 2003

In recent, the contactless IC card is widely used in traffic, access control system and so forth. Contactless smart cards use a technology that enables card readers to provide power for transactions and communications without making physical contact with the cards. Usually electromagnetic signal is used for communication between the card and the reader. Contactless card is highly suitable for large quantity of card access and data transaction. And its use becomes a general tendency more and more because of the development of RF technology and improvement of requirement for user convenience. This paper describes the hardware module to process contactless protocol for implementation contactless IC card. And the hardware module consists of specific digital logic circuits that analyze digital signal from analog circuit and then generate data & status signal for CPU, and that convert the data from CPU into digital signal for analog circuit.

• Journal of Information Processing Systems
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• v.14 no.6
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• pp.1420-1430
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• 2018

To build a successful information system, design and development should be carried out from the enterprise perspective. A complicated business is represented in various ways as technology advances, and many development methodologies have been studied from the viewpoint of technology and development. Each domain is independently designed and developed from the enterprise perspective, but there would be inclusive parts due to the integrated process wherein the definition, design, and development of business are carried out, and the design is done based on the designer's experience. This study would like to address the technique of designing screens based on the business process of the applications derived from the business. It designs the screens that appear when actual applications are completed, including how the data transfer process in the derived business process is represented and operated on the relevant screens. It designs the screen which is displayed when the actual application is completed and how the data transfer process in the derived business process is represented and operated on the relevant screen. In addition, it designs the DFD representing the overall flow of data for each business to represent the movement procedure between screens in general. Through the design method proposed in this study, the client's requirement could be confirmed to reduce the cost for redevelopment, the problem of communication between designers and developers with various experiences could be reduced, and an efficient design procedure could be provided to persons who lack design experience.

• Fourth Industrial Review
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• v.1 no.2
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• pp.17-20
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• 2021

Purpose - "Higher education of vocational education focuses on Discipline competition" This is the requirement of the education sector in China for the Application-oriented Undergraduate in the 21st century. As an integral part of Higher education vocational education, Discipline competition is not only an effective way to test the higher education reform of the Application-oriented Undergraduate, but also a measure of the level of Application-oriented Undergraduate. Research design, data, and methodology - The study conducted a survey on SPSS 24.0 Through factor analysis of 192 questionnaires data. After empirically analyzing the data, we found that the factors can be classified into four main factors. Result - This study shows that in terms of gender, boys are more susceptible to external factors and time factors while girls are more vulnerable to internal factors. And girls are more susceptible to internal factors. In terms of professional categories, non-teacher students are more likely to be hindered by external factors such as missing entry information. Conclusion - This paper assumes that there are significant differences in internal promotion and barriers in different disciplines competition.

• Journal of Drive and Control
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• v.18 no.2
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• pp.20-31
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• 2021

An excavator is a construction machine that can perform various tasks such as trenching, piping, excavating, slope cutting, grading, and rock demolishing. In the 2010s, unmanned construction equipment using ICT technology was continuously developed. In this paper, the path design process was studied to implement the output data of the decision stage, and the path design algorithm was developed. For example, the output data of the decision stage were terrain data around the excavator, excavator mechanism information, excavator hydraulic information, the position and posture of the bucket at key points, the speed of the desired bucket path, and the required excavation volume. The result of the path design was the movement of the hydraulic cylinder, boom arm, bucket, and bucket edge. The core functions of the path design algorithm are the function of avoiding impact during the excavation process, the function to calculate the excavation depth that satisfies the required excavation volume, and the function that allows the bucket to pass through the main points of the excavation process while maintaining the speed of the desired path. In particular, in the process of developing the last function, the node tracking method expressed in the path design table was newly developed. The path design algorithm was verified as this path design satisfied the JCMAS H02 requirement.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.5
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• pp.153-164
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• 2004

Under a large-scale client-server service environment, e.g., online games, encrypting data for acquiring information security often causes overload to the server and hence degradation of the service itself. Therefore, for reducing encryption payload, it is necessary to use adequately an efficient encryption scheme with respect to the security requirements of transmission data. In this paper, we propose a packet encryption scheme using multiple cryptosystems to realize such capability, which assigns a different cryptosystem according to the security requirements level. The proposed encryption scheme is applicable to internet services with heavy traffic ratios in which different kinds of data packets are incessantly transmitted between clients and servers. To show its effectiveness and superiority, the performance of the proposed encryption scheme is verified by experiments.