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Experimental Study of Flow Characteristics of in the Pump Sump (펌프 흡입부 주변의 흐름특성에 대한 실험적 연구)

  • Byeon, HyunHyuk;Yang, JaeHoon;Yoon, ByungMan;Kim, Seojun
    • Proceedings of the Korea Water Resources Association Conference
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    • 2015.05a
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    • pp.72-72
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    • 2015
  • 최근 이상기후로 집중호우와 강우패턴이 변화하고 있다. 하지만 변화하는 환경을 고려하지 않은 내배수시설 설계로 내수 침수 피해가 증가하여 인명 및 재산 피해가 급증하고 있다. 이에 도시지역의 내수침수에 대한 대책으로 재내지의 초과 우수를 하천으로 강제 배수시키기 위한 빗물펌프장의 역할이 점점 중요해지고 있다. 도심지역의 집중호우에 대응하기 위해서는 빗물펌프장의 목표 배수량을 실제 배수할 수 있는지에 대한 여부가 도시지역의 내수침수를 효율적으로 방어하는데 있어 중요한 요소가 될 것이다. 하지만 현재 빗물펌프장의 설계 시 펌프 흡입부 내 흐름특성을 고려하지 못하고 있어 펌프의 효율에 대한 불확실성이 큰 것이 사실이다. 따라서 펌프 가동 시 흡입부 주변의 흐름특성에 대한 연구가 필요하다. 기존 펌프 흡입부의 실험적 연구에서는 색소를 이용한 vortex의 생성 위치 및 경향을 정성적으로 파악하거나 ADV등의 유속계를 이용하여 흡입부 주변의 흐름특성을 지점별로 분석하는 연구들이 수행되었다. 하지만 빗물펌프장의 펌프 흡입부 주변의 흐름은 펌프 가동에 따라 매우 복잡한 와류가 발생하기 때문에 이를 방지하기 위해서는 정량적인 유속장 분석이 필요하다. 이에 본 연구에서는 비접촉식 유속 측정이 가능하고 유속장 측정이 가능하다는 장점을 갖고 있는 입자영상유속계(PIV: Particle Image Velocimetry)를 이용하여 펌프 흡입부 주변의 흐름특성을 분석하였다. 펌프 흡입부의 흐름특성을 분석한 결과 흡입관 내 유속분포의 편중 현상에 접근유속의 영향이 큰 것으로 나타났다. 또한 흡입유속에 비해 접근유속이 빠른 경우 흡입관 내 유속분포는 상류측에서 횡방향 와류가 발생하여 흡입에 방해가 되는 것을 확인하였고, 하류측으로는 흡입 방향으로 유속이 발생하는 것으로 나타났다. 따라서 향후 펌프 흡입관내 상류측부분의 와류를 감소시키기 위한 연구가 필요할 것으로 판단된다.

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Effect of Time-to-go Estimate to Impact Time Control Guidance Laws (충돌시간 제어 유도법칙에 대한 잔여비행시간 추정의 영향)

  • Kim, Mingu
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.47 no.8
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    • pp.558-565
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    • 2019
  • A lot of studies on the survivability of missiles have been widely studied, since the technology of modern warships equipped with state-of-the-art defense systems has been improved. The survivability of missiles can be improved by attacking a target simultaneously using multiple missiles. For this reason, impact time control guidance (ITCG) laws have been widely studied. This paper deals with the effect of time-to-go estimate to ITCG laws. In this paper, two kinds of time-to-go estimate are first introduced in two-dimensional and three-dimensional environment and then ITCG laws are derived using the time-to-go estimate. Numerical simulations are performed to analyze the performance of the designed ITCG laws and the effect of time-to-go estimate is discussed.

A Study for Integrating ICS Security Logs with Centralized SIEM (Security Information and Event Management) using OPC Protocol (OPC 프로토콜을 활용한 제어시스템 보안로그 전송방법 고찰 및 통합 로그서버 구축방안)

  • Kim, Jaehong;Park, Yongsuk
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.26 no.8
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    • pp.1205-1212
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    • 2022
  • Cyber threat targeting ICS (Industrial Control System) has indicated drastic increases over the past decade and Cyber Incident in Critical Infrastructure such as Energy, Gas Terminal and Petrochemical industries can lead to disaster-level accidents including casualties and large-scale fires. In order to effectively respond to cyber attacks targeting ICS, a multi-layered defense-in-depth strategy considering Control System Architecture is necessary. In particular, the centralized security log system integrating OT (Operational Technology) and IT (Information Technology) plays an important role in the ICS incident response plan. The paper suggests the way of implementing centralized security log system that collects security events and logs using OPC Protocol from Level 0 to Level 5 based on IEC62443 Purdue Model to integrate ICS security logs with SIEM (Security Information Event Management) operated in IT environment.

Asymmetric Signal Scanning Scheme to Detect Invasive Attacks (침투 공격 검출을 위한 비대칭 신호 스캐닝 기법)

  • Da Bin Yang;Ga Young Lee;Young-woo Lee
    • Smart Media Journal
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    • v.12 no.1
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    • pp.17-23
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    • 2023
  • Design-For-Security (DFS) methodology is to protect integrated circuits from physical attacks, and that can be implemented by adding a security circuit to detect abnormal external access. Among the abnormal accesses called invasive attack, microprobing and FIB circuit editing are classified as the most powerful methods because they have direct access. Microprobing deliberately inject defects into the wire of circuit through probes, or reads and changes data. FIB circuit editing is methods of reconnecting or destroying circuits to neutralize security circuits or to access data. Previous DFS methodology have responded to the attacks by detecting arrival time asymmetry between the two signals or by comparing input/output data based on encrypted communication. This study conducted to reduce hardware overhead, and the proposed circuit detects the reflected signal asymmetry generated through probe or FIB circuit editing and detects the attacks through comparison. Since the proposed security circuit reduces the size and test cycle of the circuit compared to previous studies, the cost used for security can be reduced.

A Technique for Accurate Detection of Container Attacks with eBPF and AdaBoost

  • Hyeonseok Shin;Minjung Jo;Hosang Yoo;Yongwon Lee;Byungchul Tak
    • Journal of the Korea Society of Computer and Information
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    • v.29 no.6
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    • pp.39-51
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    • 2024
  • This paper proposes a novel approach to enhance the security of container-based systems by analyzing system calls to dynamically detect race conditions without modifying the kernel. Container escape attacks allow attackers to break out of a container's isolation and access other systems, utilizing vulnerabilities such as race conditions that can occur in parallel computing environments. To effectively detect and defend against such attacks, this study utilizes eBPF to observe system call patterns during attack attempts and employs a AdaBoost model to detect them. For this purpose, system calls invoked during the attacks such as Dirty COW and Dirty Cred from popular applications such as MongoDB, PostgreSQL, and Redis, were used as training data. The experimental results show that this method achieved a precision of 99.55%, a recall of 99.68%, and an F1-score of 99.62%, with the system overhead of 8%.

Case study of Music & Imagery for Woman with Depression (우울한 내담자를 위한 MI(Music & Imagery) 치료사례)

  • Song, In Ryeong
    • Journal of Music and Human Behavior
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    • v.5 no.1
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    • pp.67-90
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    • 2008
  • This case used MI techniques that give an imagery experience to depressed client's mental resource, and that makes in to verbalism. Also those images are supportive level therapy examples that apply to positive variation. MI is simple word of 'Music and Imagery' with one of psychology cure called GIM(Guided Imagery and Music). It makes client can through to the inner world and search, confront, discern and solve with suitable music. Supportive Level MI is only used from safety level music. Introduction of private session can associate specification feeling, subject, word or image. And those images are guide to positive experience. The First session step of MI program is a prelude that makes concrete goal like first interview. The Second step is a transition that can concretely express about client's story. The third step is induction and music listening. And it helps to associate imagery more easily by used tension relaxation. Also it can search and associate about various imagery from the music. The last step is process that process drawing imagery, talking about personal imagery experience in common with therapist that bring the power by expansion the positive experience. Client A case targets rapport forming(empathy, understanding and support), searching positive recourse(child hood, family), client's emotion and positive support. Music must be used simple tone, repetition melody, steady rhythm and organized by harmony music of what therapist and client's preference. The client used defense mechanism and couldn't control emotion by depression in 1 & 2 sessions. But the result was client A could experience about support and understanding after 3 sessions. After session 4 the client had stable, changed to positive emotion from the negative emotion and found her spontaneous. Therefore, at the session 6, the client recognized that she will have step of positive time at the future. About client B, she established rapport forming(empathy, understanding and support) and searching issues and positive recognition(child hood, family), expression and insight(present, future). The music was comfortable, organizational at the session 1 & 2, but after session 3, its development was getting bigger and the main melody changed variation with high and low of tune. Also it used the classic and romantic music. The client avoids bad personal relations to religious relationship. But at the session 1 & 2, client had supportive experience and empathy because of her favorite, supportive music. After session 3, client B recognized and face to face the present issue. But she had avoidance and face to face of ambivalence. The client B had a experience about emotion change according depression and face to face client's issues After session 4. At the session 5 & 6, client tried to have will power of healthy life and fairly attitude, train mental power and solution attitude in the future. On this wise, MI program had actuality and clients' issues solution more than GIM program. MI can solute the issue by client's based issue without approach to unconsciousness like GIM. Especially it can use variety music and listening time is shorter than GIM and structuralize. Also can express client's emotion very well. So it can use corrective and complement MI program to children, adolescent and adult.

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Flavonoid Biosynthesis: Biochemistry and Metabolic Engineering (Flavonoid 생합성:생화학과 대사공학적 응용)

  • Park, Jong-Sug;Kim, Jong-Bum;Kim, Kyung-Hwan;Ha, Sun-Hwa;Han, Bum-Soo;Kim, Yong-Hwan
    • Journal of Plant Biotechnology
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    • v.29 no.4
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    • pp.265-275
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    • 2002
  • Flavonoid biosynthesis is one of the most extensively studied areas in the secondary metabolism. Due to the study of flavonoid metabolism in diverse plant system, the pathways become the best characterized secondary metabolites and can be excellent targets for metabolic engineering. These flavonoid-derived secondary metabolites have been considerably divergent functional roles: floral pigment, anticancer, antiviral, antitoxin, and hepatoprotective. Three species have been significant for elucidating the flavonoid metabolism and isolating the genes controlling the flavonoid genes: maize (Zea mays), snapdragon (Antirrhinum majus) and petunia (Prtunia hybrida). Recently, many genes involved in biosynthesis of flavonoid have been isolated and characterized using mutation and recombinant DNA technologies including transposon tagging and T-DNA tagging which are novel approaches for the discovery of uncharacterized genes. Metabolic engineering of flavonoid biosynthesis was approached by sense or antisense manipulation of the genes related with flavonoid pathway, or by modified expression of regulatory genes. So, the use of a variety of experimental tools and metabolic engineering facilitated the characterization of the flavonoid metabolism. Here we review recent progresses in flavonoid metabolism: confirmation of genes, metabolic engineering, and applications in the industrial use.

Preparation of an Inactivated Influenza Vaccine Using the Ethanol Extracts of Medical Herbs (한약재 식물 에탄올추출물을 이용한 인플루엔자 불활화백신 제작)

  • Cho, Sehee;Lee, Seung-Hoon;Kim, Seonjeong;Cheong, Yucheol;Kim, Yewon;Kim, Ju Won;Kim, Su Jeong;Seo, Seungin;Seo, Dong-Won;Lim, Jae-Hwan;Jeon, Sejin;Jang, Yo Han
    • Journal of Life Science
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    • v.32 no.12
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    • pp.919-928
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    • 2022
  • As seen in the COVID-19 pandemic, unexpected emergence of new viruses presents serious concern on public health. Especially, the absence of effective vaccines or antiviral drugs against emerging viruses significantly increases the severity of disease and duration of viral circulation among population. Natural products have served as a major source for safe and effective antiviral drugs. In this study, we examined the virucidal activity of medical herb extracts with a view to discover novel antiviral agents with desired levels of safety and antiviral efficacy. Ethanol extracts of ten selected medical herbs were tested for antioxidant activity and in-vitro cytotoxicity in various animal cell lines. Of note, the herbal extracts showed broad and potent virucidal activities against rotavirus, hepatitis A virus, and influenza A virus. The extracts of Sorbus commixta and Glycyrrhiza uralensis showed strong virucidal activities against influenza A virus. We also examined whether the extracts of Sorbus commixta and Glycyrrhiza uralensis can be used as inactivating agents to prepare an inactivated viral vaccine. In a mouse model, influenza A virus inactivated by the extracts elicited high levels of neutralizing antibodies, and the vaccination provided complete protection against lethal challenge. These results suggest that herb-derived natural products can be developed to antiviral drugs as well as inactivating agents for preparation of inactivated viral vaccines.

Target motion analysis of the respiratory gated guided radiotherapy in liver cancer patients using 4D-CT (4D-CT와 호흡동조시스템을 이용한 간암 환자의 방사선치료 표적 움직임 분석)

  • Dong, Kyung-Rae;Park, Byung-Soo;Kim, Sae-Sark;Kweon, Dae-Cheol;Goo, Eun-Hoe;Chung, Woon-Kwan
    • Journal of Radiation Protection and Research
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    • v.35 no.2
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    • pp.63-68
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    • 2010
  • The ultimate goal of radiation treatment is to use enough radiation dosage in order to examine a tumor while protecting normal tissue. Respiratory guided radiotherapy is being clinically implemented to examine a given stabilized area in order to compensate for the problems of patient breathing. This study investigates the effects of breathing movements on 40 patients with liver cancer through the actual radiation therapy plan using 4D-CT and respiratory guided radiotherapy using RPM. Using a commercial RPM respiratory gating system 4D-CT, we acquired 4D CT on multislice helical CT scanners that use different approaches to 4D CT image reconstruction. The results from analyzing forty patients according to age and direction showed no relationship between gender and transition change. The mean left-right, anteroposterior, and craniocaudal total movements were $3.19{\pm}1.29$, $5.44{\pm}2.07$, and $12.54{\pm}4.70$ mm, respectively. Changes were the largest with CC directions and as patients advanced in age, movements were larger. Therefore, as changes occur in treatment areas because of movements caused from breathing, respiratory gating system is put into operation to revise movement and can increase the radiotherapeutics effects in treating liver cancer.

Observations on the Reproductive Behavior of the Marine Medaka, Oryzias dancena (해산송사리, Oryzias dancena의 산란행동 분석)

  • Lim, Sang-Gu;Han, Hyung Kyun;Kim, Kwang Seog;Kim, Bong Seok;Baek, Hyun Min;Park, In-Seok;Gil, Hyun Woo
    • Korean Journal of Ichthyology
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    • v.24 no.3
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    • pp.220-226
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    • 2012
  • The aim of this study is to observe the reproductive behavior of the marine medaka, Oryzias dancena, and determine the factors of reproductive behavior to provide useful information for improving their artificial reproduction techniques. The reproductive behavior of the marine medaka was observed in laboratory aquaria. Once the experiment began, all of the males chased the females. The males attempted to stimulate the urogenital openings of the females. While chasing a female, a large male would bite a relatively small male's anus. Larger males expelled smaller males with biting, and the defeated males were barred from the female. After the other males were expelled, the remaining male approached and drew alongside the female. The male's dorsal and anal fins covered the female's body. Spawning began after complete covering took place. Spawning of males and females occurred simultaneously. The loadings for 2 factors were calculated. The calculation was restricted to 2 factors because these 2 factors explained about 81% of the total common variance (P<0.05) and the following factors possessed no practical significance. Two movements (biting, expelling) had high positive values for factor one. This factor related a male's defensive behavior to courtship behavior and spawning, and explained 23.1% of the total common variance (P<0.05). The second factor had high positive values for chasing, rejection, covering, and parallel swimming. This factor related a male's courtship behavior and female's defensive behavior to spawning, and explained 59.7% of the total common variance (P<0.05). This research provided basic biological data for the conservation of this species and useful information for improving their artificial reproduction techniques.