• Bulletin of the Korean Chemical Society
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• v.33 no.7
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• pp.2207-2212
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• 2012

Dimethylaluminum isopropoxide (DMAI, $(CH_3)_2AlO^iPr$) as a single precursor, which contains one aluminum and one oxygen atom, has been adopted to deposit non-stoichiometric aluminum oxide ($AlO_x$) films by low pressure metal organic chemical vapor deposition without an additional oxygen source. The atomic concentration of Al and O in the deposited $AlO_x$ film was measured to be Al:O = ~1:1.1 and any serious interfacial oxide layer between the film and Si substrate was not observed. Gaseous by-products monitored by quadruple mass spectrometry show that ${\beta}$-hydrogen elimination mechanism is mainly contributed to the $AlO_x$ CVD process of DMAI precursor. The current-voltage characteristics of the $AlO_x$ film in Au/$AlO_x$/Ir metalinsulator-metal (MIM) capacitor structure show high ON/OFF ratio larger than ${\sim}10^6$ with SET and RESET voltages of 2.7 and 0.8 V, respectively. Impedance spectra indicate that the switching and memory phenomena are based on the bulk-based origins, presumably the formation and rupture of filaments.

• Informatization Policy
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• v.21 no.1
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• pp.77-98
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• 2014

The Korean government has been promoting the establishment of comprehensive information systems as one of supports for preschools' administration. This support is expected to enhance the efficiency of preschool education support systems and to improve the quality of educational services. The gap between government's expectation on an introduction of the information system and preschool educators' expectations has also been an issue in deploying this new system. This study identifies user resistance factors for comprehensive preschool administration assistance systems' deployment. We find that the performance expectancy, social influence, effort expectancy, and the psychological cost of user resistance have impacts on the user resistance. When these factors related resistance are resolved in the process of systems' deployment, active participation in these systems by preschool educators would be increased.

• Convergence Security Journal
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• v.13 no.4
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• pp.19-25
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• 2013

The increasing demand for fast, flexible and guaranteed Quality of Service (QoS) in core networks has caused to deploy MultiProtocol Label Switching (MPLS) and Generalized MPLS (GMPLS) control plane. In GMPLS control plane, path computation and cooperation processes are one of the crucial element to maintain an acceptable level of service. The Internet Engineering Task Force (IETF) has proposed the Path Computation Element (PCE) architecture. The PCE is a dedicated network element devoted to path computation process and communications between Path Computation Clients (PCC) and PCEs is realized through the PCE Protocol (PCEP). This paper examines the PCE-based path computation architecture to include the design and implementation of PCEP. The functional modules including Finite State Machine (FSM) and related key design issues of each state are presented. In particular we also discuss internal/external protocol interfaces that efficiently control the communication channels.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.8A
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• pp.581-590
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• 2003

This paper proposes the routing path selection mechanism for source routing-based PtMP (Point-to-Multipoint) call in ATM switching system. Especially, it suggests PtMP routing path selection method that can share the maximum resource prior to the optimal path selection, guarantee the reduction of path calculation time and cycle prevention. The searching for the nearest branch point from destination node to make the maximum share of resource is the purpose of this algorithm. Therefore among neighbor nodes from destination node by back-tracking, this algorithm fixes the node crossing first the node on existing path having the same Call ID as branch node, constructs the optimal PtMP routing path. The optimal node to be selected by back-tracking is selected by the use of Dijkstra algorithm. That is to say, PtMP routing path selection performs the step of cross node selection among neighboring nodes by back-tracking and the step of optimal node selection(optimal path calculation) among neighboring nodes by back-tracking. This technique reduces the process of search of routing information table for path selection and path calculation, also solves the cycle prevention easily during path establishment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.1
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• pp.9-15
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• 2015

A CMOS band-pass delta-sigma modulator(BPDSM) and cascode class-E power amplifier have been developed CMOS for Class-S power amplifier applications. The BPDSM is operating at 1-GHz sampling frequency, which converts a 250-MHz sinusoidal signal to a pulse-width modulated digital signal without the quantization noise. The BPDSM shows a 25-dB SQNR(Signal to Quantization Noise Ratio) and consumes a power of 24 mW at an 1.2-V supply voltage. The class-E power amplifier exhibits an 18.1 dBm of the maximum output power with a 25% drain efficiency at a 3.3-V supply voltage. The BPDSM and class-E PA were fabricated in the Dongbu's 110-nm CMOS process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.15-20
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• 2016

The existing multiple modulus-based self-recovering equalization type has not been applied to initial equalization. Instead, it was used for steady-state performance improvement. In this paper, for the self-recovering equalization type that considers the multiple modulus as a desired response, the initial convergence performance was improved by extending the dynamics of the errors using error boosting and their characteristics were analyzed. Error boosting in the proposed method was carried out in proportion to a symbol decision for the equalizer output. Furthermore, having the initial convergence capability by extending the dynamics of errors, it showed excellent performance in the initial convergence rate and steady-state error level. In particular, the proposed method can be applied to the entire process of equalization through a single algorithm; the existing methods of switching over or the selection of other operation modes, such as concurrent operating with other algorithms, are not necessary. The usefulness of the proposed method was verified by simulations performed under the channel conditions with multipath propagation and additional noise, and for performance analysis of self-recovering equalization for high-order signal constellations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.4B
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• pp.298-305
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• 2003

In this paper, we proposed a high performance lookup controller for IP packet forwarding engine of ATM based label edge routers. The lookup controller is designed to provide services such as MPLS, VPN, ELL, and RT services as well as the best effort. For high speed searching for IP addresses, we employed a TCAM based hardware search device not using traditional algorithmic approaches. We also implement lookup control functions into FPGA for fast processing of packet header and lookup control. The proposed lookup controller is designed to support differenciated services for users and to process in pipelined mechanism for performance improvement. A two-step search scheme is also applied to perform lookup for the key combined with multi-field of packet header. We found that the proposed lookup controller provides the performance of about 16M packets per second through simulations.

• Journal of Engineering Education Research
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• v.15 no.2
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• pp.20-29
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• 2012

The purpose of this study was to explore the academic achievements, learning attitudes, and career compromising processes for successful undergraduate students in the College of Engineering. To achieve this goal, research was conducted to analyze whether there was a strong major-career connection among Engineering students of Seoul National University. Afterwards, differences in levels of academic achievement, learning attitude, and academic aspiration were analyzed between students who had achieved a major-career match and students who had not. As a result, it was found that the level of major-career connection was highly correlated to the level of academic achievement; furthermore, learning attitudes were strongly related to the level of motivation towards a high academic achievement, and influenced future learning attitudes as well. These findings suggest that further academic support, career guidance, and major switching policies are needed for undergraduate students in Colleges of Engineering.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.3
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• pp.298-305
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• 2016

Various NoSQL databases are more excellent to process a large amount of big data than existing relational databases such as MySQL, PostgreSQL and Oracle. Among widely used NoSQL databases, performance of HBase, Cassandra, MongoDB and Redis was comparatively assessed. For distributed processing of a large amount of data, 12 servers were connected through switching hub and Ubuntu was installed as operating system. As for benchmark tool, YCSB was applied. Read and update ratios changed from 50% and 50%, 95% and 5% and finally, 100% and 0% and each of them was assessed as 200,000 commands developed into 1,200,000 commands for each case. Cassandra was most excellent with transaction processing per second while MongoDB was most excellent with the number of processes carried out per unit time.

• The Transactions of the Korea Information Processing Society
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• v.4 no.10
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• pp.2544-2552
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• 1997

This paper presents three multiprocess models for parallel protocol implementation, that is, (1)channel communication model, (2)fork-join model, and (3)event polling model. For the specification of parallelism for each model, a parallel programming language, Par. C System, is used. to measure the performance of multiprocess models, we implemented the Internet Protocol Suite(IPS) Internet Protocol (IP) for each model by writing the parallel language on the Transputer. After decomposing the IP functions into two parts, that is, the sending side and the receiving side, the parallelism in both sides is exploited in the form of Multiple Instruction Single Data (MISD). Three models are evaluated and compared on the basis of various run-time overheads, such as an event sending via channels in the parallel channel communication model, process creating in the fork-join model and context switching in the event polling model, at the sending side and the receiving side. The event polling model has lower processing delays as about 77% and 9% in comparison with the channel communication model and the fork-join model at the sending side, respectively. At the receiving side, the fork-join model has lower processing delays as about 55% and 107% in comparison with the channel communication model and the event polling model, respectively.