• Title/Summary/Keyword: Defense mechanism

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Priority Based Multi-Channel MAC Protocol for Real-Time Monitoring of Weapon Flight Test Using WSNs

  • Min, Joonki;Kim, Joo-Kyoung;Kwon, Youngmi;Lee, Yong-Jae
    • Journal of Sensor Science and Technology
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    • v.22 no.1
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    • pp.18-27
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    • 2013
  • Real-time monitoring is one of the prime necessities in a weapon flight test that is required for the efficient and timely collection of large amounts of high-rate sampled data acquired by an event-trigger. The wireless sensor network is a good candidate to resolve this requirement, especially considering the inhospitable environment of a weapon flight test. In this paper, we propose a priority based multi-channel MAC protocol with CSMA/CA over a single radio for a real-time monitoring of a weapon flight test. Multi-channel transmissions of nodes can improve the network performance in wireless sensor networks. Our proposed MAC protocol has two operation modes: Normal mode and Priority Mode. In the normal mode, the node exploits the normal CSMA/CA mechanism. In the priority mode, the node has one of three grades - Class A, B, and C. The node uses a different CSMA/CA mechanism according to its grade that is determined by a signal level. High grade nodes can exploit more channels and lower backoff exponents than low ones, which allow high grade nodes to obtain more transmission opportunities. In addition, it can guarantee successful transmission of important data generated by high grade nodes. Simulation results show that the proposed MAC exhibits excellent performance in an event-triggered real-time application.

An Improvement of Expendable Bathythermograph Measurement Mechanism for Anti-Submarine Warfare (대잠용 수온측정계 측정 메커니즘 개선)

  • Shin, Sang-Sik;Cho, Hwan Hwi;Park, Seung Soo
    • Journal of Korean Society for Quality Management
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    • v.42 no.3
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    • pp.301-310
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    • 2014
  • Purpose: The purpose of this study is to improve a mechanism of expendable bathythermograph measurement by balancing wire resistances between plus wire part and minus wire part and by removing effects of sea water resistance between XBT(Expendable Bathythermograph) and temperature recorder. Methods: The problems are exactly found out through the analysis of XBT and temperature recorder circuit. A process of XBT manufacturing that balances wire resistances between plus wire part and minus wire part is added. Results: The results of this study are as follows; the complicated test process such as temperature accuracy test with a cistern is substituted with a simple process of XBT manufacturing such as balancing wire resistances between plus wire part and minus wire part. Then, the temperature accuracy tolerance of XBT is improved up to ${\pm}0.1^{\circ}C$. Conclusion: Consequently, balancing wire resistances and removing effects of sea water resistance improve temperature accuracy of XBT and reduce expensive and harassing process of XBT manufacturing.

Study about the Cause and Mechanism of the Itching (소양(瘙痒)의 병인.병기(病因.病機)에 대한 연구)

  • Park, Seung-Lim;Kang, Jung-Soo
    • Journal of Haehwa Medicine
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    • v.22 no.1
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    • pp.11-21
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    • 2013
  • After studying the cause and mechanism of the itching with the perspective of chronic medical books including Neijing, and the annotators, the conclusions are as follows. 1. The itching, which has correlation with the heart, is the deficiency symptom(虛症). It is generated when the lung-metal(肺金) is infected by the fire pathogen(火邪) and developed to depression(鬱), because of the heart fire flaming upward of circuit year(歲火太過). The treatment is to make metal depression scatter(金鬱泄之). 2. The itching occurs between the dermis(膚) and the epidermis(皮). 3. The itching generates when the excess of yang exuberance(熱盛極) precede the transmission of the wind-heats(風熱), the wind-cold(風寒), and the wind-dampness(風濕). It causes the blood deficiency(血虛) and the blood stasis(血瘀) because of the skin dryness. 4. The itching usually generates during summer, causes the body fever(身熱) and the dermis pain(膚痛). When it becomes worse, it causes generalized itching and vesicles at the whole body(浸淫). 5. The itching is related to the spirit(魄), which works in unconsciousness and the movement of defense qi(衛氣) in night.

Turfgrass Responses to Water Deficit: A Review (물 부족 현상으로 인한 잔디의 생리학적 반응: 리뷰)

  • Lee, Joon-Hee
    • Asian Journal of Turfgrass Science
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    • v.25 no.2
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    • pp.125-132
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    • 2011
  • Drought is a major limiting factor in turfgrass management. Turfgrass responses to water deficit depend on the amount and the rate of water loss as well as the duration of the stress condition. This review paper was designed to understand responses such as photosynthesis, canopy spectral reflectance, plant cell, root, hormone and protein alteration when turfgrass got drought stress. Furthermore, mechanisms to recover from drought conditions were reviewed in detail. However, there are still many questions regarding plant adaptation to water deficit. It is not clear that the mechanism by which plants detect water deficit and transfer that signal into adaptive responses. Turfgrass research should focus on the best management practices such as how to enhance the ability of self-defense mechanism through understanding plant responses by environmental stress.

Naturally-Occurring Novel Anticatcinogens : Conjugated Dienoic Derivatives of Linoliec Acid (CLA) (새로이 분류된 천연 항암제 : Conjugated Dienoic Derivatives of Linoleic Acid (CLA))

  • 하영래;마이클파리자
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.20 no.4
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    • pp.401-407
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    • 1991
  • Anticarcinogenic conjugated dienoic derivatives of linoleic acid (CLA) is present in grilled beef, cheese, and related foods, CLA is generated via isomerization of linoleic acid in the cow's rumen by anaerobic bacteria and food proceessing as well. Another source of CLA is its endogenous generation via the carbon centered free radical oxdation of linoleic acid. We propose that the formation and generation of CLA in vivo represents a previously unrecognized in situ "defense mechanism" against membrane attack by oxygen free radicals. The cis, 9-trans, 11 CLS isomer is selectively incorporated into cellular phospholipid, which exhibits a potent antioxidant, reduces the activation of 2-amino-3-methylimidazo, [4,5-f] quinoline (IQ) for baxterial mutagenesis, and inhibits ornithine decarboxylase(ODC) activity induced by 12-0-tetradecanoylphorbol-13-acetate (TPA). We believe that at least these biological activities of CLA explain the anticarcinogenic activity of CLA.

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Identification of Glycine max Genes Expressed in Response to Soybean mosaic virus Infection

  • Jeong, Rae-Dong;Lim, Won-Seok;Kwon, Sang-Wook;Kim, Kook-Hyung
    • The Plant Pathology Journal
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    • v.21 no.1
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    • pp.47-54
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    • 2005
  • Identification of host genes involved in disease progresses and/or defense responses is one of the most critical steps leading to the elucidation of disease resistance mechanisms in plants. Soybean mosaic virus (SMV) is one of the most prevalent pathogen of soybean (Glycine max). Although the soybeans are placed one of many important crops, relatively little is known about defense mechanism. In order to obtain host genes involved in SMV disease progress and host defense especially for virus resistance, two different cloning strategies (DD RT-PCR and Subtractive hybridization) were employed to identify pathogenesis- and defenserelated genes (PRs and DRs) from susceptible (Geumjeong 1) and resistant (Geumjeong 2) cultivars against SMV strain G7H. Using these approaches, we obtained 570 genes that expressed differentially during SMV infection processes. Based upon sequence analyses, differentially expressed host genes were classified into five groups, i.e. metabolism, genetic information processing, environmental information processing, cellular processes and unclassified group. A total of 11 differentially expressed genes including protein kinase, transcription factor, other potential signaling components and resistant-like gene involved in host defense response were selected to further characterize and determine expression profiles of each selected gene. Functional characterization of these genes will likely facilitate the elucidation of defense signal transduction and biological function in SMV-infected soybean plants.

A STUDY ON THE DEFENSE MECHANISMS IN ADOLESCENT VICTIMS OF SCHOOL VIOLENCE (학교폭력 피해청소년의 방어기제에 관한 연구)

  • Park, Young-Sook;Shin, Jee-Yong;Jhin, Hea-Kyung
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.10 no.2
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    • pp.158-168
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    • 1999
  • This study was carried out to know the main defense mechanisms used by adolescent victims of school violence. Subjects of this study are composed of 41 adolescent victims(clinical group) and 40 normal adolescents(control group). Clinical group is divided into four subgroups of inpatient, outpatient, day hospital, and school groups. Used scales are Ewha Defense Mechanisms Test(EDMT) and Staittrait anger scale. Several important results are found. Adoescent victims use neurotic defense mechanisms of neurotic and mature level less frequently than normal adolescents. In clinical group day hospital adolescents use more mature defense mechanisms than outpatient adolescents. Displacement and acting out are correlated with trait and sate anger. Somatization is correlated with trait anger, and regression is correlated with state anger significantly.

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An Encrypted Botnet C&C Communication Method in Bitcoin Network (비트코인 네크워크에서의 암호화된 봇넷 C&C 통신기법)

  • Kim, Kibeom;Cho, Youngho
    • Journal of Internet Computing and Services
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    • v.23 no.5
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    • pp.103-110
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    • 2022
  • Botnets have been exploited for a variety of purposes, ranging from monetary demands to national threats, and are one of the most threatening types of attacks in the field of cybersecurity. Botnets emerged as a centralized structure in the early days and then evolved to a P2P structure. Bitcoin is the first online cryptocurrency based on blockchain technology announced by Satoshi Nakamoto in 2008 and is the most widely used cryptocurrency in the world. As the number of Bitcoin users increases, the size of Bitcoin network is also expanding. As a result, a botnet using the Bitcoin network as a C&C channel has emerged, and related research has been recently reported. In this study, we propose an encrypted botnet C&C communication mechanism and technique in the Bitcoin network and validate the proposed method by conducting performance evaluation through various experiments after building it on the Bitcoin testnet. By this research, we want to inform the possibility of botnet threats in the Bitcoin network to researchers.

The System Position from High Firing Rate of Anti-Aircraft Gun system (고발사율 대공포 발사에 따른 체계자세 연구)

  • Hwang, Boo Il;Lee, Boo Hwan;Kim, Chi Hwan
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.6
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    • pp.611-615
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    • 2015
  • Anti-aircraft gun system is used for low-level air defense system and has more than twin guns with high firing rate in order to maximize the capability of defense. Gun's vibration and bullet's variance has a critical effect on accuracy and hit probability of weapon system such as anti-aircraft gun system with high firing rate. Typical mechanism to reduce the amount of vibration and shock during gun-fire process is very important design factor. In this paper, the suspension characteristics of the vehicle are studied for the improvement of isolating performance of gun firing system with high firing rate. Gun fire test for the vehicle is conducted and computational models using Recurdyn and Adams are created based on test results. Through this study, results of computational analysis are compared with the real test results, which includes type, location and quantity of suspension and gun mechanism are selected for anti-aircraft gun. From the result of this study, we could make basic design and consider the proper component of the system such as suspension and gun spring.