• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12C
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• pp.1020-1028
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• 2010

Relay has attracted great attention due to its inherent capability to extend the service coverage and combat shadowing in next generation mobile communication systems. So far, most relay technologies have been developed under the half-duplex (HD) constraint that prevents relays from transmitting and receiving at the same time. Although half-duplex relay (HDR) is easy to implement, it requires partitioning of resource for transmission and reception, reducing the whole system capacity. In this paper, we propose a multinser precoding and power control scheme with sum rate matching for a full-duplex (FD) multiple-input multiple-output (MIMO) relay. Full-duplex relay (FDR) can overcome the drawback of HDR by transmitting and receiving on the same frequency at the same time, while it is crucial to reduce the effect of self-interference that is caused by its own transmitter to its own receiver. The proposed precoding scheme cancels the self-interference of the FDR as well as to support multiuser MIMO. Moreover, we suggest a power allocation scheme for FD MIMO relay with the constraint that the sum rate of the relay's received data streams is equal to that of the relay's transmit data streams.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.194.1-194.1
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• 2015

Transition metal dichalcogenide (TMD) with layered structure, has recently been considered as promising candidate for next-generation flexible electronic and optoelectronic devices because of its superior electrical, optical, and mechanical properties.[1] Scalability of thickness down to a monolayer and van der Waals expitaxial structure without surface dangling bonds (consequently, native oxides) make TMD-based thin film transistors (TFTs) that are immune to the short channel effect (SCE) and provide very high field effect mobility (${\sim}200cm^2/V-sec$ that is comparable to the universal mobility of Si), respectively.[2] In addition, an excellent photo-detector with a wide spectral range from ultraviolet (UV) to close infrared (IR) is achievable with using $WSe_2$, since its energy bandgap varies between 1.2 eV (bulk) and 1.8 eV (monolayer), depending on layer thickness.[3] However, one of the critical issues that hinders the successful integration of $WSe_2$ electronic and optoelectronic devices is the lack of a reliable and controllable doping method. Such a component is essential for inducing a shift in the Fermi level, which subsequently enables wide modulations of its electrical and optical properties. In this work, we demonstrate n-doping method for $WSe_2$ on poly-4-vinylphenol and poly (melamine-co-formaldehyde) (PVP/PMF) insulating layer and adjust the doping level of $WSe_2$ by controlling concentration of PMF in the PVP/PMF layer. We investigated the doping of $WSe_2$ by PVP/PMF layer in terms of electronic and optoelectronic devices using Raman spectroscopy, electrical measurements, and optical measurements.

• The KIPS Transactions:PartC
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• v.8C no.1
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• pp.51-59
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• 2001

In order to support various QoS, IETF has proposed the Differentiated Services Model which provides discrimination service according to t the user’s requirements and payment intention intention for each traffic characteristic. This model is an excellent mechanism, which is not too c complicated in terms of the management for service and network model. Also, it has scalability that satisfies the requirement of Differentiated Services. In this paper, We define the Differentiated Services Model using feedback control, propose its control procedure, and analyze its p performance. In conventional model, non-adaptive traffic, such as UDP traffic, is more occupied the network resource than adaptive traffic, such a as TCP traffic. On the other hand, the Differentiated Services Model using feedback control fairly utlizes the network resources and even p prevents congestion occurrence due to its ability of congestion expectation.

• Journal of Korean Library and Information Science Society
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• v.41 no.2
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• pp.127-145
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• 2010

Outsourcing, importing of publishing metadata and revitalizing copy cataloging have reduced importance of traditional cataloging. Request of interoperability between other communities and business integration of related system also have changed the meaning of library catalog. Furthermore, newly declared principle and rules are totally different to existing AACR, MARC, measures to cataloging education for next generation seems to be urgently needed. In this study, firstly put together a series of discussion about future cataloging and new role of cataloging librarian, and secondly basis on it, suggest direction of cataloging education course which divided two sectors. One is for students who are undergraduated, and another is for current cataloger at working level. In basic training, it should contain principle of knowledge organization and diverse resources and its relationship, encoding scheme and its practice. The other hand, in re-education training, it should include that re-recognition about new concept of bibliographic world, changing vocabulary and encoding scheme, furthermore metadata scheme about diverse resources which library have accepted, and its integration.

• Journal of Information Technology Applications and Management
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• v.17 no.4
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• pp.157-180
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• 2010

The IT services industry is considered as the leading industry of the ubiquitous age that raises a nation's overall productivity and efficiency. Therefore, it is receiving increasing attention as the industry that can bring about economic takeoff and successful overseas market entrance for the next generation. In order to achieve successful development, the industry should be competitive and armed with strategies that well demonstrate the characteristics of IT services. Therefore, it is important to explore the competitive factors of the industry for its qualitative development from the perspectives of IT services industry policies and as well as IT services companies. This study categorized IT services into three types-system integration, IT consulting, and IT outsourcing- and then examined the competitive factors of each service type and their relationships with financial and non-financial performances. In conclusion, the current competitiveness of domestic IT services industry is attributed to institutions environment rather than its competitive advantages in technology, quality, know-how, and highly qualified human resources. In order to facilitate the sound growth of the IT industry and seek reasonable market competition, the environment that puts its priority on the improvement of institutions environment and the ability to carry out a project needs to be established. In all, this study can be utilized as an important knowledge for the establishment of polices to foster IT services industry and of strategies that raise competitiveness to maximize the performances of companies.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.9
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• pp.7-13
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• 2010

In this paper, we proposed a processor architecture that is suitable for next generation embedded applications, especially for personal information devices such as smart phones, tablet PC. Latest high performance embedded processors are developed to achieve high clock speed. Because increasing performance makes design more difficult and induces large overhead, architectural evolution in embedded processor field is necessary. Among more enhanced processor types, out-of-order superscalar cannot be a candidate for embedded applications due to its excessive complexity and relatively low performance gain compared to its overhead. Therefore, new architecture with moderate complexity must be designed. In this paper, we developed a low-cost SMT architecture model and compared its performance to other architectures including scalar, superscalar and multiprocessor. Because current personal information devices have a tendency to execute multiple tasks simultaneously, SMT or CMP can be a good choice. And our simulation result shows that the efficiency of SMT is the best among the architectures considered.

• Journal of Advanced Navigation Technology
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• v.23 no.6
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• pp.589-596
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• 2019

With the proliferation of intelligent transportation system (ITS) with dedicated short-range communication (DSRC) deployment, there are various applications requiring different throughput and reliability performance. To meet the enhanced throughput requirements in newly generated applications, IEEE 802.11bd is proposed to standardize for support of enhanced throughput and latency, preserving the fairness with previously deployed WLAN V2X devices. One of the main features of IEEE 802.11 bd is 20 MHz transmission to support the high data rate. In this paper, the primary channel selection method is proposed to guarantee the fairness with frame transmissions with 10 MHz bandwith including communications in WLAN V2X devices deployed with IEEE 802.11p. Simulation shows that the proposed channel access method for 20 MHz transmission with primary selection preserves the fairness without the change of channel access method in wide-band transmission.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.40 no.1
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• pp.1-9
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• 2003

The CNN-UM algorithm which performs the analog parallel subtraction of images has been developed and its application study to the moving target detection has been done. The CNN-UM is the state of the art computation architecture with high computational potential of analog parallel processing. It is one of the strong candidates for the next generation of computing system which fulfills requirement of the real-time image processing. One weakness of the CNN-UM is that its analog parallel processing function is not fully utilized for the inter frame processing. If two subsequent image frames are superimposed with opposite signs on identical capacitors for short time period, the analog subtraction between them is achieved. The Principle of such temporal inter-frame processing algorithm has been described and its mathematical analysis has been done. Practical usefulness of the proposed algorithm has also been verified through the application for moving target detection.

• Aerospace Engineering and Technology
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• v.1 no.1
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• pp.177-187
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• 2002

Some kinds of precision optical systems for spaceborne high resolution cameras were designed at preliminary design level and an optical design for a hyperspectral imager was performed for its development model. A Cassegrain-based catadioptric system and an unobscured reflective triplet system are illustrated in detail for spaceborne high resolution electro optical cameras which have performance of 5m resolution at an altitude of 685km and the design are evaluated in its spot-diagram and MTF to prove they have good performance enough to implement the requirements for realistic satellite payload taking the fabrication conditions and the on-orbit operation into consideration. For the development of hyperspectral imager as a next-generation payload, an optical system has been designed and elaborated. It can be divided into two parts, a catoptric telescope forming an off-axis 2 mirror type and a dispersive spectrometer which comprises collimator, grating and reimaging lens cell. From its optical design to the system characteristics are shown with the MTF performance reaching 25% approximately.

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.139-142
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• 2018

Silicon (Si) is a promising anode material for next-generation lithium ion batteries (LIBs) because of its high capacity of 4,200 mAh/g ($Li_{4.4}Si$ phase). However, the large volume expansion of Si during lithiation leads to electrical failure of electrode and rapid capacity decrease. Generally, a binder is homogeneously mixed with active materials to maintain electrical contact, so that Si needs a particular binding system due to its large volume expansion. Polyvinyl alcohol (PVA) is known to form a hydrogen bond with partially hydrolyzed silicon oxide layer on Si nanoparticles. However, the decrease of its cohesiveness followed by the repeated volume change of Si still remains unsolved. To overcome this problem, we have introduced the electrospinning method to weave active materials in a stable nanofibrous PVA structure, where stresses from the large volume change of Si can be contained. We have confirmed that the capacity retention of Si-based LIBs using electrospun PVA matrix is higher compared to the conservative method (only dissolving in the slurry); the $25^{th}$ cycle capacity retention ratio based on the $2^{nd}$ cycle was 37% for the electrode with electrospun PVA matrix, compared to 27% and 8% for the electrodes with PVdF and PVA binders.