Defending denial-of-service attacks in SDNFV-enabled cloud computing

Phan, Van Trung Soongsil University 2017 국내석사

In my thesis, I propose a novel S2eH scheme to tackle Denial-of-Service (DoS) attacks in the Software-Defined Network Functions Virtualization (SDNFV) cloud computing environment. I firstly introduce a new machine learning hybrid model for DoS attack classification based on Support Vector Machine (SVM) and Self Organizing Map (SOM) algorithms to enhance the performance of classification network traffic. The proposed combination mainly focuses on taking advantages of two classification algorithms by utilizing both algorithm advantages that SVM takes a little time to produce outputs with a high accuracy and SOM makes a reliable prediction based on their neurons. Then, I propose an enhanced History-based IP Filtering scheme (eHIPF) to improve attack detection rate and speed. Finally, I propose a novel mechanism combining both the machine learning hybrid model SVMs-SOM and the eHIPF scheme, called S2eH, to make a DoS attack defender in the SDNFV-enabled cloud computing. The S2eH testbed is implemented in the SDNFV cloud environment with Service Function Chaining. Through practical experiments in this testbed, it is proved that the proposed SVMs-SOM combination and eHIPF scheme outperforms existing mechanisms for DoS attack classification and detection. By analyzing comprehensive experiments conducted with various DoS attack levels, I prove that the novel S2eH mechanism is an effective and innovative approach to defend DoS attacks in the SDNFV-based cloud computing. 본 논문에서는 Software-Defined Network Functions Virtualization (SDNFV) Cloud computing 환경에서 서비스 거부 공격을 저지하는 새로운 S2eH 스키마를 제안한다. 먼저, DoS 공격 분류를 위해 Network 분류 성능을 높이는 Support Vector Machine (SVM) 과 Self-Organizing Map(SOM) 알고리즘 기반 새로운 Hybrid Machine Learning을 소개한다. 제안된 결합 시스템은 주로 두 가지 분류 알고리즘의 이점을 가져오는데 초점을 둔다. SVM은 짧은 시간에 높은 정확도로 분류를 하고, SOM은 SOM의 신경망기반으로 신뢰성이 높은 예측을 한다. 또한, 공격 탐지 비율과 속도를 개선하기 위해 History 기반 IP Filtering 스키마(eHIPF)를 제안한다. 본 논문에서는 SDNFV가 가능한 Cloud Computing 에서 DoS공격을 방어하기 위해 SVMs-SOM을 결합한 Hybrid Machine Learning 모델과 eHIPF 스키마를 결합한 새로운 메커니즘 S2eH을 제안한다. S2eH testbed는 Service Function Chaining이 가능한 SDNFV Cloud 환경에서 실험했다. 이 testbed에서 실제 실험을 통해 본 논문에서 제안된 SVMs-SOM 결합과 eHIPF 스키마가 DoS공격 분류와 탐지에 다른 메커니즘보다 좋은 결과 가져오는 것을 증명했다. 다양한 DoS공격 레벨로 수행 된 포괄적인 실험을 분석하여 새로운 S2eH메커니즘이 SDNFV기반 Cloud computing에서 DoS 공격을 방어하기 위한 효과적이고 혁신적인 방법임을 증명했다.

Research on insurance fraud and regulations on prevention of automobile insurance fraud : experiences from the United States of America and proposals for Vietnam

Phan, Thi Huong Giang TLBU Graduate School of Law 2019 국내석사

링 마우스 : 손가락 움직임에 의한 컴퓨터 무선 입력 장치

Phan, Ke Hien 한국산업기술대학교 일반대학원 2018 국내석사

국문요약 링 마우스: 손가락 움직임에 의한 컴퓨터 무선 입력 장치 한국산업기술대학교 일반대학원 전자공학과: 판게히엔 지도교수: 정 두 희 이 논문에서는 링과 같이 손가락으로 감싸는 컴퓨터 용 무선 장치를 연구했습니다. Ring Mouse는 Bluetooth를 통해 컴퓨터에 무선으로 연결된 마우스 역할을하는 스마트 장치입니다. 손가락 움직임으로 컴퓨터의 마우스 커서를 제어 할 수 있습니다. 마이크로 컨트롤러 Cortex M4와 함께 nRF52832를 사용함으로써 우리는 전력 효율이 높고 비용 효율적인 회로를 만들었습니다. 모션 데이터는 MPU-9250 모듈을 사용하여 획득합니다. 장치의 기계적 케이스는 3D 인쇄 기술로 설계 및 제작되었습니다. ABSTRACT Ring Mouse: A Wireless Input Device for Computers by Finger Motions By Phan Ke Hien Advisor: Professor Jung Doo Hee Course for Electronics Engineering Graduate School Korea Polytechnic University In this thesis, we studied a wireless device for the computer which is carried on the finger like a ring. Ring Mouse is a smart device that acts as a mouse that is connected wirelessly to a computer via Bluetooth. One can control the mouse cursor on the computer with finger motions. By using nRF52832 with microcontroller Cortex M4, we made a circuit that is power-efficient and cost-effective. Motion data is acquired by using an MPU-9250 module. The mechanical case of the device is designed and made by 3D printing technologies.

Expanding constraint theory to determine well-posedness of large mathematical models

Phan, Phan University of Southern California 2011 해외박사(DDOD)

Mathematical modeling represents one of the major tools for the conception and management of the ever increasing complexity of systems engineering. Unfortunately, present approaches to math modeling suffer from several theoretical problems which include: model consistency, computational allowability, management of the topologically complex flow of software algorithms, rearrangement of independent and dependent variables, distinction between the model structure and software programs and perhaps the most challenging, the exponential explosions resulting from the management of even medium sized models as well as the large models of the thousands of dimensions necessary to define and manage the complex systems of the future. Constraint theory was designed to solve the above problems employing a rigorous application of graph theory and attempts to employ the generalizability of mathematics to extend the math model manager's conceptual understanding from half a dozen dimensions to the desired thousands of dimensions. Constraint theory (CT) went through several stages of detail and maturity, starting with the PhD dissertation in the 1960's and progressing through several papers and two other PhD research programs. CT's present frontier can be characterized by the Constraint Theory book written by Dr. George Friedman and published by Springer in 2005. CT differs from linear programming (LP) in several ways. LP requires a full model of explicit mathematical expressions in linear form whereas CT employs a meta-model based upon relevancy between general (linear or non-linear) relations and variables. CT seeks to determine a model consistency and computational allowability without having to actually solve for a specific solution set whereas LP assumes that the problem is well-posed while attempting to solve for an optimal solution within a given constrained trade space. As mentioned above, the exponential explosions associated with the management of thousand-dimensional models is truly enormous, on the order of 2 N examinations of a model's N equations are required to determine consistency, for example. CT has converged this process---which would take several universe lifetimes even with nanosecond computer cycle times---by a factor of trillions. This convergence is based on an ordered series of graph theoretic steps involving connected-ness, tree-ness, circuit-ness and cluster-ness. A constraint theoretic structure called the "Basic Nodal Square" (BNS) is identified as the kernel of constraint in a math model. An n x n BNS is essentially a complete sub-system of n relations and n variables within the overall model. However, Friedman's book effectively stops at the identification of circuit clusters of approximately 30 relations, and suggests that BNS within these clusters can be found by modern computers in a few hours. It is suggested that perhaps more research can employ the topological property of adjacency to converge the search for BNS within larger circuit clusters. The central contribution resultant from this investigation realizes and improves the computational efficiency of BNS search by factors of trillions, asymptotically (see Figure 10-2). This improvement has been accomplished by innovative application of graph theory, topology, algorithm analysis and linear algebra, which were not addressed to sufficient depth in the original efforts. Leveraging research results in graph theory since the early 1970's, several BNS search methods, based on nodal adjacency, circuit adjacency and nodal degree, have been developed and compared against the baseline (brute-force) approach of 2N. Primary key research findings and enablers include: (a) Decomposition of a model graph into its connected components by employing the graph-theoretic concept of a spanning tree and applying the depth-first search algorithm. (b) Innovation of the edge-centric method, over the legacy approach of vertex-centricity, to identify, and remove, internal trees (or bridges) within a connected component. (c) Further isolation of circuit clusters containing potential BNS by using the graph-theoretic concept of articulation point (or separating vertex). (d) Rigorous proof of circuit vector-based theorems to simplify the computational complexity of constructing unions of adjacent circuits, and thus reduce BNS search space. (e) Application of vectorial dot product to detect adjacency among circuits, and overlapping among nodes or BNSs. (f) Development and demonstration of a meta-meta-model graph to represent overlapping among nodes and to reduce the solution-time for BNS search, from exponential to polynomial. Additional accomplishments further improve the utility of CT by developing an integrated set of efficient computing algorithms to determine model consistency and computational allowability. The output of these algorithms can also advise the model builder of repair alternatives to correct any model inconsistency detected. Such algorithms are necessary to bridge the gap between theoretical abstracts and practical realization of CT in terms of an effective computer-assisted tool for math model management.

(A) study of groupthink in Viet Nam online communities

Phan, Nhu Quynh Soongsil University 2016 국내석사

Groupthink phenomenon has studied in a number of authors for over the past 40 years and now this topic is still getting a lot of attention. Groupthink occurs for a group of closely linked together in a provocative situational context. The majority of authors have studied this phenomenon for the offline groups. Today with the development of science and technology, many people often study and work via the Internet with online communities. Therefore, this study tries to explore and examine the phenomenon of Groupthink that may affect how the quality of decision makes for online communities. This empirical study towards the respondents was in Vietnam who currently participate online community. The survey was conducted from October 20, 2015 to November 10, 2015 for a period of 20 days. The total number of surveys collected 321 samples, after removing the invalid samples, and 285 samples were used to conduct the analysis. According to the analysis, Cohesion of the group does not affect to closed-mindedness of the group and Provocative situational context does not affect to Overestimation of the group. Furthermore, Overestimation of the group also does not affect to Symptoms of defective decision-making in online communities. This result has some differences with the basic theoretical model that Janis had proposed. I hope that the results of this experimental study will contribute useful for further research in this field in the future. 집단사고 현상은 지난 40년동안 많은 저자들이 연구되어 지금까지 여전히 많은 관심을 받고 있다. 집단사고는 자극적인 상황에서 지나친 응집력 그룹에 대한 자주 발생한다. 현재까지 대다수의 저자들이 오프라인 그룹에 대한 집단사고를 연구해 왔는데, 최근에 ICT과학 기술의 발전으로 인터넷을 통하여 사람들이 공부하거나, 일하거나, 오락활동을 하는 온라인 커뮤니티 활동이 증가하고 있다. 따라서 본 연구는 집단사고 현상이 의사 온라인 커뮤니티 활동과 온라인 커뮤니티의 의사결정 품질에 영향을 미치는지 탐색하고자 한다. 본 연구는 실증 분석을 하기 위하여 온라인 활동에 참석 경험이 있는 일반인을 대상으로 설문 조사 실시를 하였으며 조사 기간은 2015년 10월 20일부터 2015년 11월 10일까지 20일간 온라인을 통해 실시하였다. 회수된 설문 응답 수는 총 321부 가 회수되었으며, 이 중 결측치가 있는 경우나 불성실한 응답의 경우 제외하고 최종 분석에서는 285부의 설문지를 활용하였다. 분석 결과는 그룹의 지나친 응집력이 폐쇄적 마이드에 영향을 미치지 않고 자극적인 상황적 요인이 그룹에 대한 과대평가에 영향을 미치지 않은 것으로 나타났으며, 그룹에 대한 과대평가가 잘못된 그룹의사결정의 증상에 미치지 않은 것으로 나타났다. 이러한 결과는 집단사고에 대한 제니스가 제시하였던 기초 이론적 모델과 차이가 있다고 볼 수 있다. 본 연구에서는 제시된 분석결과를 통하여 향후 이 분야에 관한 더 깊은 연구에 계속 적용된다면 바람직할 것이다.

Impact of mismatch lesion on long-term outcome of intravascular ultrasound guided percutaneous coronary intervention

Phan, Tan Quang 중앙대학교 대학원 2019 국내박사

연구목적 본 연구는 참조혈관 크기와 목표병변의 혈관크기가 다른 불일치병변 (mismatch lesion)이 혈관내 초음파를 이용한 경피적 관동맥 중재술의 결과에 미치는 영향을 평가하기위해 하였다. 연구방법 참조혈관 크기와 목표병변의 혈관크기가 다른 불일치병변은 근위부와 원위부 참조혈관 내강이 최소 1.0 mm 이상 또는 가장 작은 참조혈관 내강이 30 % 이상 차이가 나는 경우는 불일치혈관군(mismatch group)으로 하였고, 차이가 없었던 군은 일치혈관군 (non-mismatch group)으로 하였다. 총 1,706 병변을 후향적으로 분석하여 불일치혈관군 411 병변과 일치혈관군 1,295 병변으로 나누었다. 성향점수분석 (Propensity score matching) 후 최종 분석을 위해 각 군에서 397 병변을 선택하였고, 주요 심장 사건으로 사망, 심근 경색 및 목표병변 재개통술을 평균 5년간 관찰하여 분석하였다. 결과 대상군의 임상적 특성 및 혈관 조영 특성은 성향점수매칭후 두 군 간에 차이가 없었다. 일치혈관군과 비교했을 때, 불일치혈관군은 시술 시간이 더 길었고 (53.8±16.2 vs. 45.2±10.7 분, p<0.001), 조영제 사용량 (179.6±53.2 vs. 161.4±31.2 ml, p<0.001) 과 스텐트의 수(1.19±0.43 vs. 1.07±0.25, p<0.001) 가 더 많았다. 불일치혈관군은 스텐트시술후 추가적인 풍선확장술 최적화 치료가 더 많은 경우에서 필요하였고 (79.6% vs. 53.9%, p<0.001), 풍선확장시간이 길었으며 (2.98±1.75 vs. 1.91±0.92, p<0.001) 및 사용한 최대압력이 (19.5±3.9 vs. 16.7±3.7 atm, p<0.001) 더 높았다. 관동맥 중재술 동안, 불일치혈관군은 주요 합병증이 (7.8% vs. 4.3%, p=0.037) 더 높았고, 시술 성공률이 낮았다 (91.4% vs. 95.5%, p=0.022). 최종 혈관조영상에서, 불일치혈관군은 최소 내강 직경 (2.62±0.45 vs. 2.90±0.57 mm, p<0.001)이 작았고, 잔존 협착이 더 높았고 (11.3±4.5% vs. 9.4±6.2%, p<0.001), 시술 성공률이 낮았다 (93.2% vs. 96.7%, p=0.023). 최종 혈관내초음파에서 불일치혈관군은 최소 스텐트 면적이 더 작았고 (6.39±2.09 vs. 6.93±2.77 mm2, p=0.002), 불완전한 스텐트 밀착 및 스텐트 가장자리 박리가 (6.3% vs. 3.0%, p=0.029 and 2.5% vs. 0.8%, p=0.045)을 더 많았다. 하지만 스텐트 혈전증은 두 군 간에 유의한 차이가 없었다 (p=0.317). 추적 관찰 결과 불일치혈관군은 심장사망 (HR: 2.54, 95%CI:1.36-4.75, p=0.003)과 목표혈관 재개통술 (HR: 2.73, 95%CI:1.59-4.71, p<0.001)에 주로 기인한 주요심장사건(HR: 2.23, 95%CI:1.56-3.12, p<0.001)의 위험이 더 높았다. 결론 불일치 혈관병변은 관동맥 중재술이 가능한 병변이지만, 관동맥 중재술에 혈관내초음파를 사용하는데도 바람직하지 않은 시술결과와 나쁜 임상경과를 보였다. 본 연구 결과는 협착형태에서 불일치 혈관병변의 영향을 분석하였고, 적절한 접근법을 찾기 위해 전향적 연구에서 검증이 필요하다. Objectives To evaluate the impact of mismatch lesion on the outcome of percutaneous coronary intervention (PCI) with intravascular ultrasound (IVUS) guidance. Material and Methods Mismatch lesion was defined as the difference between the proximal and distal reference lumen diameters (RLD) of ≥1.0 mm or ≥30% of the smallest RLD. Total 1,706 lesions were retrospectively analyzed and divided into two groups, including 411 lesions in Mismatch group and 1,295 lesions in non-mismatch group. After propensity score matching, 397 lesions in each group were selected for final analysis. Major adverse cardiac events (MACE) was the composite of death, myocardial infarction and target lesion revascularization (TLR). Results The baseline and angiographic characteristics of participants were well balanced after propensity score matching. Compared with non-mismatch group, mismatch group PCI needed more procedure time (53.8±16.2 vs. 45.2±10.7 minutes, p<0.001), contrast amount (179.6±53.2 vs. 161.4±31.2 ml, p<0.001) and number of coronary stent (1.19±0.43 vs. 1.07±0.25, p<0.001). Mismatch group also required more frequently use of post-stenting optimization (79.6% vs. 53.9%, p<0.001) with more inflation times (2.98±1.75 vs. 1.91±0.92, p<0.001) using higher maximum pressure (19.5±3.9 vs. 16.7±3.7 atm, p<0.001). During PCI, mismatch group encountered more major complications (7.8% vs. 4.3%, p=0.037) and lower procedure success rate (91.4% vs. 95.5%, p=0.022). On final angiogram, mismatch group had smaller minimum lumen diameter (2.62±0.45 vs. 2.90±0.57 mm, p<0.001), higher residual stenosis (11.3±4.5% vs. 9.4±6.2%, p<0.001) and lower angiographic success rate (93.2% vs. 96.7%, p=0.023). On final IVUS, mismatch group achieved smaller minimal stent area (6.39±2.09 vs. 6.93±2.77 mm2, p=0.002) along with higher rate of incomplete stent apposition and stent edge dissection (6.3% vs. 3.0%, p=0.029 and 2.5% vs. 0.8%, p=0.045, respectively). Follow-up data during median of 5 years showed that mismatch group had higher risk of MACE (HR: 2.23, 95%CI:1.56-3.12, p<0.001), mainly driven from cardiac death (HR: 2.54, 95%CI:1.36-4.75, p=0.003) and TLR (HR: 2.73, 95%CI:1.59-4.71, p<0.001). Conclusions Mismatch lesion posed significant challenging during PCI that led to unfavorable procedural results and worse clinical outcomes even with IVUS guidance. These results need to be validated in prospective studies to determine the role of mismatch lesion in stenosis morphology classification and to find the suitable approach to deal with this lesion type.

Epidemiology of hand, foot, and mouth disease in Southern Vietnam in 2012-2022

Phan Thi Ngoc Uyen Graduate School of Public Health, Yonsei Universit 2024 국내석사

Background: With a 50-year history, Hand, foot, and mouth disease (HFMD) remains a significant public health issue in the Western Pacific, ranking in Vietnam's top 5 communicable diseases. This study analyzes surveillance data in southern Vietnam, the country's highest HFMD burden region. Methods: An ecological study examined HFMD epidemiological characteristics and factors contributing to severe cases across all 20 provinces in southern Vietnam from 2012 to 2022, using national notifiable diseases surveillance system data. Results: Southern Vietnam reported 686,358 HFMD cases, including 104 fatalities, with an incidence rate of 175 cases per 100,000 population. Cases peaked in April during the COVID-19 pandemic. Over 90% occurred in children under three, with males comprising 59%. The Mekong River Delta showed higher severity and mortality risks (OR 2.64, 95% CI: 2.44-2.86 and OR 2.48, 95% CI: 1.10-5.95). Individual factors associated with a higher incidence of severe cases included younger age, male gender, and ethnic minority status. At the provincial level, lower proportions of the population using clean water, and lower numbers of hospital beds per 10,000 population were associated with a higher incidence of severe cases (OR 0.98, 95% CI: 0.97-0.99; and OR 0.99, 95% CI: 0.98-0.99, respectively). Conclusion: HFMD's epidemiology in southern Vietnam aligns with the Western Pacific. Post-COVID-19, adaptive surveillance is vital, and addressing severe cases requires multifaceted interventions, emphasizing healthcare infrastructure, and improved water hygiene.

Preparation of Near-Infrared-Absorbing Nanoparticles for Cancer Bioimaging and Photothermal Treatment : 암에 대한 바이오이미징 및 광열 치료법을 위한 근적외선 흡수 나노입자 제조

PHAN, THI TUONG VY 부경대학교 대학원 2019 국내박사

Cancer is among the leading causes of death worldwide. Cancer theragnosis agents with both cancer diagnosis and therapy abilities would be the next generation of cancer treatment. Recently, nanomaterials with strong absorption in near-infrared (NIR) region have been explored as promising cancer theragnosis agents for bio-imaging and photothermal therapy. In this dissertation, we reported the preparation of several advanced nanomaterials systems with biocompatible, strong NIR-absorbing properties. We offered the novel green method to synthesis NIR-absorbing agents to alter the costly and toxic traditional methods. The in vitro and in vivo photothermal anticancer activity results of the designed nanoparticles evidenced their promising potential in cancer treatment. The nanoparticles also gave the good amplitude of photoacoustic signals, which facilitates the imaging of tumor tissues using a non-invasive photoacoustic tomography system. Thus, our works highlight the great potential of using NIR-absorbing agents as theranostic nanoplatforms for cancer imaging-guided therapy.

Development of theta-burst ultrasound as a non-invasive paradigm for pain management and bidirectional neuromodulation : Development of theta-burst ultrasound as a non-invasive paradigm for pain management and bidirectional neuromodulation

Phan Thuy Tien 과학기술연합대학원대학교 기초과학연구원(IBS) 2024 국내박사

이 연구에서는 초음파의 통증 관리 대한 새로운 응용 기법 및 관련 기전에 대한 연구를 수행하였습니다. 제 1 장에서는 만성 신경병증성 통증에서 척수 성상교세포의 기능 및 역할을 연구하였고, 치료기법으로써 BDNF 관련 경로를 치료 전략의 대상으로 제안하였습니다. 제 2 장에서는 저강도 초음파의 진통 효과와 관련한 성상교세포의 역할과 이에 기반한 통증 완화의 가능성을 고찰하였습니다. 이러한 연구 결과들은 다양한 형태의 신경 조율을 위한 저강도 초음파의 잠재력을 보여주며, 만성 통증 조절을 위한 표적 솔루션으로써의 초음파의 임상 적용 가능성을 제시하고 있습니다. 제 1 장: 말초 부분 신경손상으로 인한 신경병증성 통증 기전에서의 성상교세포 특이적 기능 연구 신경병증성 만성 통증은 기존의 진통 치료로는 치료하기 어려운 임상적인 문제로 인식되고 있습니다. 척수 성상교세포에 대한 연구는 발전되고 있지만, 말초 좌골신경 부분적인 눌림 손상에 따른 신경병증성 통증에서의 성상교세포의 기능 변화와 역할에 대한 연구는 부족한 실정입니다. 이 연구에서는 만성 신경병증성 통증과 관련된 척수 성상교세포의 형태와 기능 변화를 통해서 초기 통증 반응에서 만성 통증으로의 이행되는 과정에서의 성상교세포의 중요성을 보여주었습니다. 또한, 기계적 알로디니아 (이질통) 지속과정에 있어서 척수내 뇌유래 신경영양인자(BDNF) 발현 증가와 성상교세포의 상관관계를 통해, 신경병증성 통증에서의 척수 신경계의 성상교세포 활성화와 BDNF 신호 전달의 연관성을 확인했습니다. 그리고 BDNF/TrkB 억제제를 통한 성상교세포의 활성화 억제가 기계적 알로디니아 완화를 유도함을 입증함으로써, 신경병증성 만성 통증 치료 및 관리를 위한 새로운 유형의 치료 방법을 제안하였습니다. 제 2 장: 초음파를 통한 신경병적 통증 관리 초음파 자극은 비침습적인 신경 조절 기술로 통증 치료의 새로운 기술로 조명되고 있습니다. 본 연구에서는 부분 압박 손상에 의한 신경병증성 통증에 대한 저강도 Theta-burst 초음파 (LI-cTBUS)의 진통 효과 및 관련 기전에 대한 연구를 수행하였습니다. 이 연구에서는 LI-cTBUS 가 기계적 자극에 대한 반응의 역치 증가를 통해서 현저한 신경병증성 만성 통증 상황하에서의 기계적 자극에 대한 유의한 수준의 진통 효과를 나타냄을 관찰하였으며, 이는 기계적 자극에 반응하는 TRPA1 의 활성화를 통해 중재됨을 규명하였습니다. 또한, LI-cTBUS 는 척수 성상교세포의 기능 조절 및 척수 통증 유발 인자로써 중요한 세포외 BDNF 의 흡수를 촉진함으로써 척수 BDNF/KCC2 경로의 균형 유지에 중요한 역할을 수행함을 규명하였습니다. 이 연구 결과는 LI-cTBUS 가 신경병증성 통증의 기계적 알로디니아 (이질통)를 효과적으로 완화시킨다는 것을 보여 주는 결과이며, 저강도 초음파 기술을 통한 신경병증성 만성 통증에 대한 진통유발 기전에서의 성상교세포와 기계적 감수기인 TRPA1 가 중요한 역할에 연구 결과를 보여주고 있습니다. In this study, we collectively explore innovative applications of ultrasound for pain management and brain modulation. Chapter I highlights astrocytes' role in chronic neuropathic pain, proposing a BDNF-related pathway as a target for treatment strategies. Chapter II introduces low-intensity ultrasound's analgesic effects mediated through astrocyte involvement, demonstrating potential for pain alleviation. These chapters underscore ultrasound's potential for diverse neurological applications, offering targeted solutions for pain and brain function modulation.   Chapter I Neuropathic pain poses a formidable clinical challenge due to its persistent nature and resistance to conventional analgesic approaches. Although considerable insights have been gained into spinal astrocyte involvement in neuropathic pain, the alterations and contributions of these cells subsequent to a partial crush injury (PCI) remain inadequately explored. Our investigation centered on delineating the structural and functional adaptations of spinal astrocytes during the enduring phase of neuropathic pain employing a specific injury model. This model serves as a valuable tool in comprehending the mechanisms perpetuating chronic pain and underscores the indispensability of astrocytes in pain maintenance and sensitization. Through the examination of mechanical allodynia, a painful sensation in response to innocuous tactile stimuli, and the correlation with increased levels of brain-derived neurotrophic factor (BDNF) along with reactive astrocytes, we identified a potential correlation between astrocytic activity and BDNF signaling. Ultimately, our research provides evidence that inhibiting astrocyte activation through a BDNF/TrkB inhibitor alleviates mechanical allodynia, underscoring the therapeutic potential of targeting glial BDNF-related pathways for pain management. These findings offer critical insights into the cellular and molecular dynamics of neuropathic pain, paving the way for innovative and targeted treatment strategies for this challenging condition.   Chapter II Ultrasound stimulation, an emerging non-invasive neuromodulation approach, shows promise in pain management despite lacking a clear mechanism of action. This study unveils the analgesic impact of a specific ultrasound variant, low-intensity theta burst ultrasound with a continuous paradigm (LI-cTBUS), on neuropathic pain triggered by partial crush injury (PCI). We observe a significant pain-alleviating effect, characterized by an increase in mechanical thresholds, during and after LI-cTBUS treatments on the spinal cord. Interestingly, this analgesic effect is mediated through the activation of mechanosensitive TRPA1. Furthermore, LI-cTBUS induces a critical involvement of spinal astrocytes in pain modulation, facilitating the uptake of extracellular BDNF by these astrocytes, leading to the rebalance of the spinal BDNF/KCC2 pathway. Additionally, LI-cTBUS exhibits efficacy in reducing spinal astrogliosis and levels of astrocytic GABA, both in vivo and in vitro. Overall, this study demonstrates the efficient mitigation of mechanical allodynia in neuropathic pain through LI-cTBUS, shedding light on its therapeutic promise in pain management. The study underscores the indispensable role of astrocytes and the involvement of mechanosensitive TRPA1 in mediating LI-cTBUS's analgesic effects, offering significant scientific insights into potential therapeutic applications.

Does a leader pay a price for being servant? the negative effects of servant leadership behaviors on leaders' well-being

Phan Thanh Thao Graduate School, Korea University 2021 국내석사

This study adopts job demands-resources theory as an overarching framework to examine the enactment of a servant leadership style and its potential negative effects on leaders themselves. Whereas much of the existing research literature about servant leadership focuses on how these leaders can improve follower and organizational outcomes, this study specifically investigates how this leadership style may act as an additional demand on the leaders who engage in it. Based on temporal separation data collected in Vietnam, the results indicated that engaging in servant leadership leads to emotional exhaustion by generating psychological job demand in terms of role overload. Moreover, the study identifies a boundary condition on the extent to which adopting servant leadership behaviors would be more stressful, by taking into account their followers’ characteristics. Specifically, the effect of servant leadership on leaders’ well-being is more strongly negative when leaders’ perception of subordinates’ manipulative intention is high. Theoretical, practical implications and directions for future research are discussed.