• International Journal of Aeronautical and Space Sciences
• /
• v.14 no.2
• /
• pp.133-139
• /
• 2013

Morphing aircraft capable of varying their wing form can operate efficiently at various flight conditions. However, radical morphing of the aircraft leads to increased structural complexities, resulting in occurrence of dynamic instabilities such as flutter, which can lead to catastrophic events. Therefore, it is of utmost importance to investigate and understand the changes in flutter characteristics of morphing wings, to ensure uncompromised safety and maximum reliability. In this paper, a study on the flutter characteristics of the folding wing type morphing concept is conducted, to examine the effect of changes in folding angles on the flutter speed and flutter frequency. The subsonic aerodynamic theory Doublet Lattice Method (DLM) and p-k method are used, to perform the flutter analysis in MSC.NASTRAN. The present baseline flutter characteristics correspond well with the results from previous study. Furthermore, enhancement of the flutter characteristics of an aluminum folding wing is proposed, by varying the outboard wing folding angle independently of the inboard wing folding angle. It is clearly found that the flutter characteristics are strongly influenced by changes in the inboard/outboard folding angles, and significant improvement in the flutter characteristics of a folding wing can be achieved, by varying its outboard wing folding angle.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.27 no.1
• /
• pp.751-760
• /
• 2009

This research aims to develop the strategy and method to enhance the reliability of image matching results and improve the efficiency of the matching process by utilizing LIDAR data in the main image matching processes. In this work, we present the methods to utilize LIDAR data in the selection of matching entities, the search for the matched entities and the evaluation of the matching results. The proposed method has been applied to medium-resolution digital aerial images and LIDAR data acquired at the same time. The results have been analyzed in comparison with an existing method using a virtual horizontal surface rather than LIDAR DEM. This analysis indicates that the proposed method can show significantly more improved performance than the existing method. The results of this study can contribute to the improvement of the currently available commercial image matching software and the enhancement of the DEM derived from LIDAR data and matching results.

• Korean Journal of Organic Agriculture
• /
• v.28 no.3
• /
• pp.367-386
• /
• 2020

The significance of this study was to analyze the quality value of organic livestock pork for the first time based on the results of managing and testing the cycling organic farming of black pork and vegetables within farm for two years. The results of analysis could be summarized as follows. First, the pork of experimental group with crop-livestock cycling farming showed the excellent quality and high consumer preference compared to the control group of general pork or pork from non-crop-livestock cycling organic farming. In the content ratio of Omega-3 as a representative essential fatty acid, it was 1.46 that was about 2.8 times more than general pork (0.52). In case of Omega-6, it had about 2.5 times more than general pork. Especially, the U/S ratio value which was the content ratio of Unsaturated Fatty Acid (UFA, U) of Saturated Fatty Acid (SFA, S), was largely shown in pork (2.93) from cycling organic farming. Second, it would be necessary to maintain the economies of scope shown in crop-livestock cycling organic farming, and the high quality value of livestock products. For this, there should be a value chain model that could realize the economies of scope and economies of scale at the same time based on scaling and diversification through cooperative organization between farmers. Through this, it would be possible to establish a cycling model called 'community cooperative agriculture' by forming local internal markets through cooperation of production-processing and integration of distribution-sale-consumption. For the managerial activation of this cooperative organization, the government should promote/support the small crop-livestock cycling organic farming cooperative organization in local unit. For securing the reliability of crop-livestock cycling organic agricultural products and crop-livestock cycling organic livestock products, it would be necessary to review the introduction of Participatory Guarantee System (PGS).

• Proceedings of the Korea Information Processing Society Conference
• /
• 2017.04a
• /
• pp.315-318
• /
• 2017

Nowadays, Distributed Denial of Service (DDoS) attacks have gained increasing popularity and have been a major factor in a number of massive cyber-attacks. It could easily exhaust the computing and communicating resources of a victim within a short period of time. Therefore, we have to find the method to detect and prevent the DDoS attack. Recently, there have been some researches that provide the methods to resolve above problem, but it still gets some limitations such as low performance of detecting and preventing, scope of method, most of them just use on cloud server instead of network, and the reliability in the network. In this paper, we propose solutions for (1) handling multiple DDoS attacks from multiple IP address and (2) handling the suspicious attacks in the network. For the first solution, we assume that there are multiple attacks from many sources at a times, it should be handled to avoid the conflict when we setup the preventing rule to switches. In the other, there are many attacks traffic with the low volume and same destination address. Although the traffic at each node is not much, the traffic at the destination is much more. So it is hard to detect that suspicious traffic with the sampling based method at each node, our method reroute the traffic to another server and make the analysis to check it deeply.

• KIISE Transactions on Computing Practices
• /
• v.22 no.4
• /
• pp.178-183
• /
• 2016

To enhance the reliability of programs, developers use fuzzing tools in test processes to identify vulnerabilities so that they can be fixed ahead of time. In this case, the developers consider the security-related vulnerabilities to be the most critical ones that should be urgently fixed to avoid possible exploitation by attackers. However, developers without much experience of analysis of vulnerabilities usually rely on tools to pick out the security-related crashes from the normal crashes. In this paper, we suggest a static analysis-based tool to help developers to make their programs more reliable by identifying security-related crashes among them. This paper includes experimental results, and compares them to the results from MSEC !exploitable for the same sets of crashes.

• Journal of the Korean Society of Safety
• /
• v.19 no.4 s.68
• /
• pp.141-149
• /
• 2004

The automobile equipped with a gasoline engine uses the ignition coil, namely, a high voltage generator, to make the mixed fuel ignited and burned in the combustion chamber, which results in the power to drive the engine. The ignition coil functions to convert a low voltage of the primary into a hiか voltage of the secondary by switching method, which will be transmitted to the electrode. Here, if the ignition coil has a defect even a little, it cannot function well. In this study, it was chosen epoxy molding ignition coil in recently and epoxy resin which is insulation material as specimens, and it was measured the characteristics of the partial discharge occurring to the specimens when those were applied to a voltage, and thereby, it was researched and analyzed the distribution of phase angle, amount and count of discharge due to the changing voltage, And as the result is applying to the actual automobile ignition system, it can be expected the enhancement of the performance of the ignition coil and the reliability of the electrical equipment.

• Journal of Advanced Navigation Technology
• /
• v.12 no.2
• /
• pp.170-179
• /
• 2008

This study designed model that could scientifically and objectively evaluate a level of informatization of construction companies in consideration of informatization characteristics and limitations identified in researches related to the evaluation of informatization level of construction companies, so at to create the e-business environment for the construction companies including the enhancement of informatization consciousness and to improve capacity to carry out informatization. To do this, the study defined requirements to develop new model of construction informatization level and the characteristics of construction companies, and developed components of informatization level model and measuring methods that could meet the requirements based on theories and literature. The developed informatization level model were reviewed for validity and reliability through statistical method by carrying out the questionnaire survey on 200 companies along with an advisory group of experts. As the result of this study, we could suggest the directions for informatization to narrow the gap between the current level of informatization and the managerial goals in construction company.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.9
• /
• pp.2050-2055
• /
• 2012

Since the wireless sensor networks become pervasive, various application-specific requirement have been emerged and suggested. Among them, reliability and real-time service are ones of big research challenges since sensed information is useless if a packet is lost and delivered later than deadline. Even though many research works have been proposed, they was designed to meet one of both requirements. To solve above problem, in this paper, we propose how to extend current protocol to meet two requirements together. More detailed, Mint Route protocol is revised to meet specific real-time requirement, (m,k)-firm stream in wireless sensor networks. Since the main operations in MintRoute are very similar to definition of (m,k)-firm stream, extension is achieved by modifying some parts of procedure. Finally, the simulation results are given and analyzed to validate the its suitability for reliable and real-time requirement.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.3A
• /
• pp.230-236
• /
• 2007

This paper presents a resource management mechanism for the mesh networking in IEEE 802.15.3 High-rate WPAN. IEEE 802.15 TGS is standardizing the MAC and PHY for mese networking. This task group researches the mechanism that are extension of network coverage without increasing transmit power of receive sensitivity, and studies the enhanced reliability via route redundancy. In this paper we propose the distributed resource management scheme that is fairly using the channel resource in the piconet without centralized piconet coordinator. Each DEV reserves the channel time and broadcasts its information. This scheme has unfairness for later associated DEV because of preoccupation of earlier associated DEVs. This paper presents the method that fairly allocates the channel time in MAC layer. And we evaluate the performance enhancement using simple simulations.

• Polymer(Korea)
• /
• v.34 no.1
• /
• pp.52-57
• /
• 2010

The low viscous epoxy resin(bisphenol F) with carboxylic acid as the reductants was introduced for high performance and reliability in the ACA with a low melting point alloy filler system. The curing characteristics of the epoxy resin and temperature dependant viscosity characteristic of epoxy resin at the melting temperature of LMPA were investigated by dynamic mode of differential scanning calorimetry (DSC) and rheometer, respectively. Based on these thermo-rheological characteristics of epoxy resin and LMPA, the optimum process system was designed. In order to remove the oxide layer on the surface of LMPA particle, three different types of carboxyl acid-based reductant were added to the epoxy resin. The wetting angles were about $18^{\circ}$ for carboxypropyldisilioxane, and $20.3^{\circ}$ for the carboxy-2-methylethylsiloxane, respectively.