베트남의 Facebook 소셜 네트워크를 통한 기후변화 대응 평가

Tran Thi Mai Phuong,Nguyen Khac1,이달희,박태윤,한신 대한지구과학교육학회 2019 대한지구과학교육학회지 Vol.12 No.1

전 세계에서 베트남은 기후 변화에 가장 큰 영향을 받는 국가 중 하나이다. 현재 베트남의 기후 변화에 대 한 대응 활동은 텔레비전, 신문, 라디오, 인터넷 등과 같은 미디어에 의존하고 있다. Facebook은 베트남 사 람들이 가장 많이 사용는 소셜 네트워크이다 (베트남 의 페이스북 이용자는 5800만명으로 세계 7위). 그러 나 상대적으로 그것을 기후변화 대응에 이용하고자 하 는 관심은 적은편이다. 이 논문에서는 Facebook의 Audience Insight Tool(AIT)과 온라인 사회학 조사 방법 을 활용하여 Facebook을 통한 기후 변화 대응 활동의 현재 상태 및 효율성을 평가했다. 베트남 Facebook의 기후 변화 대응 팬 페이지의 수는 15개 정도이며, 그중 가장 인기 있는 곳의 팔로워 수가 94,721명에 이른다. 이 연구에서는 베트남에서 가장 방문자가 많은 기후 변화 대응 팬 페이지 2곳을 조사하고 평가 한 결과, Facebook을 통한 기후 변화 대응은 예상 한 것만큼 큰 효과가 없었다. 또한 온라인 설문 조사를 통해 이러한 문제의 원인을 파악해 보고자 하였다. 이 결과는 앞으 로 기후 변화 대응을 할 때 Facebook과 같은 소셜 네트 워크의 강점을 부각시키면서 해결책을 찾고자 하는 기 관들에게 과학적인 밑거름이 될 것이다. Vietnam is one of the countries most affected by climate change. Therefore, communication activities on climate change in Vietnam are focused with various media such as television, newspapers, radio, internet etc. In particular, Facebook social network is a potential media but less interested and developed. In this topic, Audience Insight tool of the Facebook social network and the online sociological survey method were conducted to assess the current status and effectiveness of climate change communication activities via Facebook in Vietnam today. Vietnam ranks seventh in the world with 58 million users. However, the number of climate change communication fanpages has only about 15 fanpages with the largest number of followings is 94,721 persons. Among of the 10 most contented Facebook users in Vietnam today, there is no fanpage related to climate change. The results of research and evaluation two fanpages of climate change communication that are the most and most frequent followers in Vietnam showed that climate change communication via Facebook in Vietnam is not as effective as expected. At the same time, online survey results also pointed out the causes of the above problems. This is the scientific basis for management agencies to find the solutions to promote the strength of Facebook social network in climate change communication in the future.

Trade Liberalization Schedules and Members' Development Characteristics: How are They Connected and Why do They Matter to Trade Agreements?

Khac Lich Hoang(Khac Lich Hoang ),Duc Bao Nguyen(Duc Bao Nguyen ) 세종대학교 경제통합연구소 2022 Journal of Economic Integration Vol.37 No.4

This study examines whether the length of the implementation periods of regional trade agreement (RTA) in relation to trade liberalization schedules and the level of development of member countries affect members' trade. The analysis finds that RTAs formed by partner countries with a similar level of economic development lead to increased trade among members than among North-South RTAs during a shorter transition period of trade and tariff liberalization, regardless of the degree of integration being shallow or deep. The average long-term effects of RTAs formed by developing countries on members' trade diminish 15 years after their implementation. In distinguishing trade direction from developed to developing countries and vice versa, we noted that direction-specific South-North RTAs appear to take less time to see larger increases in Southern exports to the Northern members than direction-specific North-South RTAs do.

The Acetylcholinesterase Inhibitory Activity of Alkaloids and Iridoids from Rauvolfia cambodiana Pierre ex Pit

Ninh Khac Thanh Tung,Nguen Chi Mai,Ninh Khac Ban,Duong Thi Hai Yen,Bui Huu Tai,Phan Van Kiem,Jong Seong Kang 한국분석과학회 2023 학술대회논문집 Vol.2023 No.5

Assess the phenolic content of healthy and viroid-infected apples with HPLC-PDA-ESI-MS/MS analysis

Khac Thanh Tung Ninh,Thi Phuong Duyen Vu,In Sook Cho,Kyung Tae Kim,Seo Young Yang,Young Ho Kim,Huyng Min Kim,Jong Seong Kang 한국분석과학회 2022 학술대회논문집 Vol.2022 No.5

Smart PZT-interface for wireless impedance-based prestress-loss monitoring in tendon-anchorage connection

Khac-Duy Nguyen,김정태 국제구조공학회 2012 Smart Structures and Systems, An International Jou Vol.9 No.6

For the safety of prestressed structures such as cable-stayed bridges and prestressed concrete bridges, it is very important to ensure the prestress force of cable or tendon. The loss of prestress force could significantly reduce load carrying capacity of the structure and even result in structural collapse. The objective of this study is to present a smart PZT-interface for wireless impedance-based prestress-loss monitoring in tendon-anchorage connection. Firstly, a smart PZT-interface is newly designed for sensitively monitoring of electro-mechanical impedance changes in tendon-anchorage subsystem. To analyze the effect of prestress force, an analytical model of tendon-anchorage is described regarding to the relationship between prestress force and structural parameters of the anchorage contact region. Based on the analytical model, an impedance-based method for monitoring of prestress-loss is conducted using the impedance-sensitive PZT-interface. Secondly,wireless impedance sensor node working on Imote2 platforms, which is interacted with the smart PZTinterface, is outlined. Finally, experiment on a lab-scale tendon-anchorage of a prestressed concrete girder is conducted to evaluate the performance of the smart PZT-interface along with the wireless impedance sensor node on prestress-loss detection. Frequency shift and cross correlation deviation of impedance signature are utilized to estimate impedance variation due to prestress-loss.

Capacity Maximization for an RF Energy-harvesting Cooperative Cognitive Radio Network

Khac-Khiem Nguyen,Duc-Phuc Vuong,Le Danh Khanh 대한전자공학회 2018 IEIE Transactions on Smart Processing & Computing Vol.7 No.5

This work considers a cooperative cognitive radio network including a primary system with a primary transmitter-receiver pair (PT-PR) and a secondary system with a secondary transmitter-receiver pair (ST-SR). In order to access the licensed band allocated to primary users, the ST plays the role of a decode-and-forward relay in order to forward primary signals to the PR. In particular, after receiving the primary signals, the ST first uses a power-splitting energyharvesting method to harvest energy and decode the primary signals. Then, the ST superimposes its information on the decoded primary signals, and use the harvested power to transmit the superimposed signal to the PR and the SR. We here devote our efforts to formulating and solving an optimization problem aimed at maximizing the capacity obtained by secondary users while also guaranteeing quality of service for the primary users. Simulation results clearly show that our solution significantly improves the achievable capacity of secondary users.

Influence of the Thermochemical Sludge Pretreatment on the Nitrification of A/O Reactor with the Removal of Phosphorus by Simultaneous Precipitation

Khac-Uan Do,J. Rajesh Banu,S. Kaliappan,ICK-TAE YEOM 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.2

In the present study, a laboratory scale anoxic/oxic (A/O) reactor is used for the removal of nutrient and sludge reduction. Phosphorus removal was achieved through simultaneous precipitation, and sludge production was reduced through thermochemical pretreatment. The main objective of the study was to investigate the influence of sludge pretreatment on the nitrification rate. Total phosphorus in the effluent was maintained around 0.5 ~1.0 mg/L by simultaneous precipitation, using coagulant alum at 2.2 mole ratio. Before simultaneous precipitation,the nitrification rate of the A/O reactor was found to be 0.050 g N-NH4+/g MLVSS.d. The thermochemical sludge pretreatment began on the 120th day at pH 11 and 80oC. The initiation of sludge pretreatment brought about a significant reduction of the A/O reactor nitrification rate,which fell to 0.038 g N-NH4+/g MLVSS/day. The effect of sludge pretreatment was reflected in the reduction of the nitrogen removal efficiency from 85 to 74%. Recycling of the thermochemically pretreated sludge accounted for 57%sludge reduction, which had an adverse influence on the nitrification rate of the system.

Quantitative Assessment of Friction Characteristics of Single-Layer MoS₂ and Graphene Using Atomic Force Microscopy

Khac, Bien-Cuong Tran,Chung, Koo-Hyun American Scientific Publishers 2016 Journal of nanoscience and nanotechnology Vol.16 No.5

<P>Atomically thin layered materials such as MoS2 and graphene have attracted a lot of interest as protective coating layers for micro- and nano-electromechanical devices based on their superior mechanical properties and chemical inertness. In this work, the frictional characteristics of single layer MoS2 and graphene prepared by the mechanical exfoliation method were quantitatively investigated using atomic force microscopy. The results showed that both MoS2 and graphene exhibited relatively low friction forces of 1 similar to 3 nN under normal forces ranging from 1 to 30 nN. However, a higher increase in the friction force as the normal force increased was observed in the case of MoS2. The differences in the adhesion characteristics and mechanical properties of atomically thin layered materials may influence the puckering of the layer, which in turn influences the frictional behavior.</P>

Experimental Investigation of ECDM for Fabricating Micro Structures of Quartz

Khac-Ha Nguyen,이평안,김보현 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

Recently, the utilization of electrochemical discharge machining (ECDM) has proved to have potential for enhancing the machiningefficiency and accuracy of micro-drilling and milling for glass. However, there is a lack of information about the machining conditionsfor milling in quartz materials, which have different characteristics than glass. In ECDM, gas film and sparks are generated on atool when voltage is applied between the tool and a counter electrode. Workpiece materials are removed mainly by the heat of thesparks. The spark generation is affected by both the voltage and electrolyte conditions. This study investigated the ECDMcharacteristics according to machining parameters, such as electrolyte level, electrolyte concentration, pulse voltage, offset pulsevoltage, pulse on-time, pulse off-time, and tool feedrate. Surface roughness and sharpness of the rims and edges were observed underdifferent machining conditions. Based on the investigation of the machining conditions, micro structures, including micro grooves andcolumns, were machined on quartz material.

EM Impedance-based Tension Monitoring of Cable-Anchorage in Mooring System of Offshore Structure

Khac-Duy Nguyen,Po-Young Lee,Jeong-Tae Kim 대한조선학회 2011 대한조선학회 학술대회자료집 Vol.2011 No.6

For offshore structure moored by cable system, the stability of the structure is dependent on tensile force of the cables. The loss of cable force may result in large displacement and unbalance of the structure. This study presents an electromechanical impedance-based method for tension monitoring of cable-anchorage in mooring system of offshore structure. In order to achieve the objective, the following approaches are implemented. Firstly, an PZT-Interface is introduced to monitor tensile force of cable. Once installed into the cable-anchorage, the PZT-interface works like a cantilever plate with imperfectly fixed boundary. The loss of cable force is represented by the weakness of the fixed boundary. Secondly, the variations of electromechanical (EM) impedance of the PZT-interface due to the variations of cable force are investigated. Several index like root mean square deviation, correlation coefficient deviation and frequency shift are utilized to capture these changes. Finally, the feasibility of the method is evaluated on a lab-scale cable-anchorage model.