• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.8
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• pp.3946-3965
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• 2018

Network anomaly detection in Software Defined Networking, especially the detection of DDoS attack, has been given great attention in recent years. It is convenient to build the Traffic Matrix from a global view in SDN. However, the monitoring and management of high-volume feature-rich traffic in large networks brings significant challenges. In this paper, we propose a moving window Principal Components Analysis based anomaly detection and mitigation approach to map data onto a low-dimensional subspace and keep monitoring the network state in real-time. Once the anomaly is detected, the controller will install the defense flow table rules onto the corresponding data plane switches to mitigate the attack. Furthermore, we evaluate our approach with experiments. The Receiver Operating Characteristic curves show that our approach performs well in both detection probability and false alarm probability compared with the entropy-based approach. In addition, the mitigation effect is impressive that our approach can prevent most of the attacking traffic. At last, we evaluate the overhead of the system, including the detection delay and utilization of CPU, which is not excessive. Our anomaly detection approach is lightweight and effective.

• Special Issue of the Society of Naval Architects of Korea
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• 2011.09a
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• pp.63-69
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• 2011

Exhaust gases of a vessel from a main engine, a diesel generator and an incinerator contain very harmful substances like soot, $SO_2$ and NOx. Careful design of funnel shape is required to prevent those harmful exhaust gases from influencing on accommodation and a fan room. Meanwhile, the exhaust gases are also hot enough to damage electronic devices like radar. Therefore the funnel design should be considered so that electronic devices are not directly exposed to the exhaust gas in the strong stern wind. This study may propose guidelines of optimum design criterion for the anti-thermal damage design of the electronic devices and anti-recirculating design of harmful exhaust gas near the accommodation. From CFD analyses, we can understand that the major factors affecting the exhaust gas dispersion are the large scale mixing by separation vortices and the sluggish flow in the recirculation region. We hope that the funnel flow analysis around ship's funnel is used for practical optimum funnel design to minimize the exhaust gas dispersion by adjusting the funnel shape, the position of the exhaust pipe, the shape of bulwark, the exhaust direction of air ventilated an engine room and the angle of the exhaust pipe.

• Journal of Information Display
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• v.4 no.1
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• pp.29-33
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• 2003

We have investigated the effects of hole-injection buffer layer in organic light-emitting diodes using copper phthalocyanine (CuPc), poly(vinylcarbazole)(PVK), and Poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate) (PEDOT: PSS) in a device structure of $ITO/bufferr/TPD/Alq_3/Al$. Polymer PVK and PEDOT:PSS buffer layer were produced using the spin casting method where as the CuPc layer was produced using thermal evaporation. Current-voltage characteristics, luminance-voltage characteristics and efficiency of device were measured at room temperature at various a thickness of the buffer layer. We observed an improvement in the external quantum efficiency by a factor of two, four, and two and half when the CuPc, PVK, and PEDOT:PSS buffer layer were used, respectively. The enhancement of the efficiency is assumed to be attributed to the improved balance of holes and elelctrons resulting from the use of hole-injection buffer layer. The CuPc and PEDOT:PSS layer function as a hole-injection supporter and the PVK layer as a hole-blocking one.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.280-281
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• 2007

본 논문에서는 생체 내에 삽입하거나 연속적으로 혈당을 모니터링하기 위하여 제작된 무효소 혈당세서의 바이오 패키징 및 특성 최적화에 관하여 고찰하였다. 3전극을 갖는 동일한 센서구조에서 sensitivity를 최대화하기 위해 평면형 백금전극을 사용한 센서, 메조포러스 구조가 작동전극에 형성된 센서, 메조포러스 구조가 작동전극과 보조전극에 형성된 무효소 혈당센서를 설계, 제작하고 비교하였다. 각각의 센서는 0.009${\mu}A$ $mM^{-1}cm^{-2}$, 5.46${\mu}A$ $mM^{-1}cm^{-2}$, 7.75${\mu}A$ $mM^{-1}cm^{-2}$의 sensitivity를 가졌다. 또한 생체 이식되었을 때 혈액 속에서 글루코스응답을 얻는 데에 있어 방해종인 Ascrobic Acid와 Acetaminophen의 반응을 최소화하고, 혈액 내의 단백질들이 전극에 엉겨 붙는 것을 막기 위해 생체 적합한 물질인 Nafion 을 패키징 멤브레인으로 적용하여 센서를 제작하였다. 이 센서는 0.36${\mu}A$ $mM^{-1}cm^{-2}$의 sensitivity를 가졌다.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.207.1-207.1
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• 2013

Tantalum oxide has been extensively investigated as one of the promising Resistive switching materials applicable to Resistive Dynamic Access Memories. Impedance spectroscopy offers simultaneous measurements of electrical and dielectric information, separation of electrical origins among bulk, grain boundaries, and interfaces, and the monitoring of electrical components. Such benefits have been combined with the resistive states of resistive switching devices which can be described in terms of equivalent circuits involving resistors, capacitors, and inductors, The current work employed pulsed laser deposition in order to prepare the oxygen-deficient tantalum oxide. The fabricated devices were controlled between highresistance and low-resistance states in controlled current compliance modes. The corresponding electrical phenomena were monitored both in the dc-based current-voltage characteristics and in the ac-based impedance spectroscopy. The origins of the electrical switching are discussed towards optimized ReRAM devices in terms of interfacial effects.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.8
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• pp.229-240
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• 2021

The environment friendly lifestyle and the green product trend have motivated corporates to develop and adopt sustainable business practices. However, an increasing number of corporations have engaged in greenwashing practices to create the appearance of environmental responsibility. By employing the theory of reasoned action, the paper investigated a model linking corporate greenwashing and consumers' green purchase intentions with the mediating role of green trust and green word-of-mouth about green electronic devices in Vietnam. Using an online survey via Email, Zalo, and Wechat, data was obtained from 308 Vietnamese consumers who have been purchasing green electronic devices. Based on the responses of the participants from the questionnaires conducted, data analysis was conducted by using SEM in AMOS version 23. This investigation shows that corporate greenwashing negatively affects consumers' green trust, green word-of-mouth, and their green buying intentions. Additionally, the paper verifies that green trust and green word-of-mouth mediate the relationships between greenwashing and consumers' green purchase intentions. These results reinforce the extant understanding of greenwashing and its consequences. Finally, the study not only stimulates future research but serves as a reference for business managers, scholars, and students who are interested on the topic of environmental sustainability, new product development, and green brands.

• Journal of Sensor Science and Technology
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• v.31 no.4
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• pp.238-243
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• 2022

In this study, a pyrene-core single molecule with amino (-NH₂) functional group material was hybridized using ZnO quantum dots (QDs). The suppressed performance of the 1-aminopyrene (1-PyNH₂) single molecule as an emissive layer (EML) in light-emitting diodes (LEDs) was exploited by adopting the ZnO@1-PyNH₂ core-shell structure. Unlike pristine 1-PyNH₂ molecules, the ZnO@1-PyNH₂ hybrid QDs formed energy proximity levels that enabled charge transfer. This result can be interpreted as an improvement in surface roughness. The uniform and homogeneous EML alleviates dark-spot degradation. Moreover, LEDs with the ITO/PEDOT:PSS/TFB/EML/TPBi/LiF/Al configuration were fabricated to evaluate the performance of two emissive materials, where pristine-1-PyNH₂ molecules and ZnO@1-PyNH₂ QDs were used as the EML materials to verify the improvement in electrical characteristics. The ZnO@1-PyNH₂ LEDs exhibited blue luminescence at 443 nm (FWHM = 49 nm), with a turn-on voltage of 4 V, maximum luminance of 1500 cd/m², maximum luminous efficiency of 0.66 cd/A, and power efficiency of 0.41 lm/W.

• Journal of IKEEE
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• v.26 no.1
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• pp.111-118
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• 2022

In this paper, we studied 4H-SiC CMOS that can be integrated with high-voltage SiC power devices. After designing the CMOS on a 4H-SiC substrate, we compared the electrical characteristics with the reliability of high temperature operation by TCAD simulation. In particular, it was confirmed that changing HfO₂ as the gate dielectric for reliable operation at high temperatures improves the thermal properties compared to SiO₂. By researching SiC CMOS devices, we can integrate high-power SiC power devices with SiC CMOS for excellent performance in terms of efficiency and cost of high-power systems.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.5
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• pp.1059-1066
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• 2024

Cosmic radiation poses a significant threat to the reliability of electronic devices. Cosmic radiation mainly consists of high-energy particles emitted from the sun, and there is no protection device to absorb or disperse these particles in the vacuum of space. Exposure to these high-energy particles can cause fatal damage to semiconductor devices, especially memory devices, and this can have serious implications for the entire space industry. Therefore, in this paper, we propose a new memory bit cell design method that can maintain high reliability in a space radiation environment.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.211-214
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• 2009

In this paper we will outline the opportunities for flexible OLED devices, both for display and solid-state lighting applications. We will present our recent data, and discuss future challenges, for low power consumption phosphorescent OLED technology fabricated on flexible substrates to enable a new generation of energy efficient electronic devices.