• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7C
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• pp.685-695
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• 2002

In this paper, we propose a RRS(real resource simulator) that supports the development and operational test of network management system before the development of real resources. The components of the RRS are the MOT(Managed Object Table) that holds the current status information of real resources, the SDT(Simulation Data Table) that holds the characteristics of real resources defined by user, the support functions that generate the random values and random interval values, the scheduling table that holds the sequence of events, and the main kernel. Users can set up behaviors of the RRS by extended-GDMO description. We present the structure of our extended-GDMO compiler and activities of RRS. We also show the interaction between user and the RRS, interaction between the RRS and the agent, and interaction among the NMS, the agent and the RRS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.10
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• pp.1290-1300
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• 2016

Recently, various middle box services have been developed and applied to provide network functions to end nodes of the network. Especially, network virtualization is increasingly proceeding by applying the virtualization technologies of cloud computing field to network field, and network platforms for various flexible services are being developed to connect among the virtual network devices. Carrier-grade Network Address Translation (CGNAT) is also one of these flexible network services. This paper designs and implements the DPDK-based CGNAT framework that provides flexibility and maximizes address translation throughput. Our framework achieves 15.5 times higher throughput than the address translation service by Linux kernel.

• Nuclear Engineering and Technology
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• v.50 no.8
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• pp.1306-1313
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• 2018

The randomness and incipient nature of certain faults in reactor systems warrant a robust and dynamic detection mechanism. Existing models and methods for fault diagnosis using different mathematical/statistical inferences lack incipient and novel faults detection capability. To this end, we propose a fault diagnosis method that utilizes the flexibility of data-driven Support Vector Machine (SVM) for component-level fault diagnosis. The technique integrates separately-built, separately-trained, specialized SVM modules capable of component-level fault diagnosis into a coherent intelligent system, with each SVM module monitoring sub-units of the reactor coolant system. To evaluate the model, marginal faults selected from the failure mode and effect analysis (FMEA) are simulated in the steam generator and pressure boundary of the Chinese CNP300 PWR (Qinshan I NPP) reactor coolant system, using a best-estimate thermal-hydraulic code, RELAP5/SCDAP Mod4.0. Multiclass SVM model is trained with component level parameters that represent the steady state and selected faults in the components. For optimization purposes, we considered and compared the performances of different multiclass models in MATLAB, using different coding matrices, as well as different kernel functions on the representative data derived from the simulation of Qinshan I NPP. An optimum predictive model - the Error Correcting Output Code (ECOC) with TenaryComplete coding matrix - was obtained from experiments, and utilized to diagnose the incipient faults. Some of the important diagnostic results and heuristic model evaluation methods are presented in this paper.

• Journal of Fashion Business
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• v.26 no.5
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• pp.135-152
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• 2022

This study aimed to evaluate the user experience of hearable devices for seniors and suggest possible development directions. A literature review, case study, and in-depth interviews were conducted. Based on the literature review, convenience, accessibility, transmissibility, wearability, aesthetics, and interest were determined as the user experience factors of hearable devices. Then, in-depth interviews were conducted with 12 participants aged 60 or older regarding four devices. Participants tried four different types of wireless earphones which were selected based on a case study: open-type, kernel-type, neckband-type, and earring-type. Regarding convenience, the participants preferred to carry small devices and regarding accessibility, participants responded positively for most product types. For transmissibility and wearability, there were differences depending on whether devices were put on correctly, but the participants preferred products that did not wholly block external sounds. For aesthetics, participants preferred small and cutting-edge designs. Interest was noticeable among those who had not used the devices before, and for stability, the neckband-type was the most preferred. Based on the results we suggest designing small cutting-edge designs and button-type assist devices, not blocking the external sound, providing a participation program, simplifying device functions, and establishing a method that can be combined with and stored in clothes and a delivery method that can signal danger.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.258-266
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• 2013

We propose adaptive detection algorithm to reduce a false alarm by considering the characteristics of the random noise on the detection system based on a seismic sensor. The proposed algorithm consists of the first step detection using kernel function and the second step detection using detection classes. Kernel function of the first step detection is obtained from the threshold of the Neyman-Pearon decision criterion using the probability density functions varied along the noise from the measured signal. The second step detector consists of 4 step detection class by calculating the occupancy time of the footstep using the first detected samples. In order to verify performance of the proposed algorithm, the detection of the footsteps using measured signal of targets (walking and running) are performed experimentally. The detection results are compared with a fixed threshold detector. The first step detection result has the high detection performance of 95% up to 10m area. Also, the false alarm probability is decreased from 40% to 20% when it is compared with the fixed threshold detector. By applying the detection class(second step detector), it is greatly reduced to less than 4%.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.4
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• pp.247-254
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• 2013

In this paper, dynamic response analysis of a heave compensation system is performed for offshore drilling operations based on multibody dynamics. With this simulation, the efficiency of the heave compensation system can be virtually confirmed before it is applied to drilling operations. The heave compensation system installed on a semi-submersible platform consists of a passive and an active heave compensator. The passive and active heave compensator are composed of several bodies that are connected to each other with various types of joints. Therefore, to carry out the dynamic response analysis, the dynamics kernel was developed based on mutibody dynamics. To construct the equations of motion of the multibody system and to determine the unknown accelerations and constraint forces, the recursive Newton-Euler formulation was adapted. Functions of the developed dynamics kernel were verified by comparing them with other commercial dynamics kernels. The hydrostatic force with nonlinear effects, the linearized hydrodynamic force, and the pneumatic and hydraulic control forces were considered as the external forces that act on the platform of the semi-submersible rig and the heave compensation system. The dynamic simulation of the heave compensation system of the semi-submersible rig, which is available for drilling operations with a 3,600m water depth, was carried out. From the results of the simulation, the efficiency of the heave compensation system were evaluated before they were applied to the offshore drilling operations. Moreover, the calculated constraint forces could serve as reference data for the design of the mechanical system.

• The KIPS Transactions:PartA
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• v.12A no.5 s.95
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• pp.451-460
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• 2005

We present a methodology to design energy-efficient data paths using FPGAs. Our methodology integrates domain specific modeling, coarse-grained performance evaluation, design space exploration, and low-level simulation to understand the tradeoffs between energy, latency, and area. The domain specific modeling technique defines a high-level model by identifying various components and parameters specific to a domain that affect the system-wide energy dissipation. A domain is a family of architectures and corresponding algorithms for a given application kernel. The high-level model also consists of functions for estimating energy, latency, and area that facilitate tradeoff analysis. Design space exploration(DSE) analyzes the design space defined by the domain and selects a set of designs. Low-level simulations are used for accurate performance estimation for the designs selected by the DSE and also for final design selection We illustrate our methodology using a family of architectures and algorithms for matrix multiplication. The designs identified by our methodology demonstrate tradeoffs among energy, latency, and area. We compare our designs with a vendor specified matrix multiplication kernel to demonstrate the effectiveness of our methodology. To illustrate the effectiveness of our methodology, we used average power density(E/AT), energy/(area x latency), as themetric for comparison. For various problem sizes, designs obtained using our methodology are on average $25\%$ superior with respect to the E/AT performance metric, compared with the state-of-the-art designs by Xilinx. We also discuss the implementation of our methodology using the MILAN framework.

• Journal of Educational Research in Mathematics
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• v.22 no.3
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• pp.429-444
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• 2012

As one of the trials for a systematic approach to mathematics terms which occupies an important place in teaching and learning mathematics, compositions of listed terms in 2011 elementary mathematics curriculum in Korea are discussed in this study. To this end, listed terms are classified in view of three points and looked for their characteristics, from which implications are found out for elementary mathematics teaching and learning First of all classifications into grade-group and domain-specific terms, then into newly coined terms and terms from everyday life, and then into korean terms and chinese character terms and english terms are attempted. Next, terms with a kernel and terms without a kernel are distinguished, and in this process, term-sets are presented. Finally, object terms, operation terms, relationship terms, measure terms, conditions terms, graphics terms, name terms are classified. Based on these results, the following implications for elementary mathematics teaching and learning are suggested. First, it should be considered that many of the listed terms in 2011 curriculum are newly coined and chinese character terms. Second, the interconnections between terms should be considered. Third, a variety of roles and functions of the terms should be considered.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.701-705
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• 2002

This paper describes implementation of IPv6-IPv4 transition toolbox named as 6TALK(IPv6 TrAansLator of Krv6) and some scenarios using 6TALK which enables IPv6 island to connect other IPv6 island or IPv4 island seamlessly. 6TALK implements some transition mechanisms suggested in NGTrans Working Group of IETF. Those mechanisms are composed of basic mechanism, tunneling, and applied mechanism such as DSTM. 6TALK provides functions which enable IPv6 network at the edge of existing network to communicate with IPv4 network by using these transition mechanisms. As major transition mechanisms in 6TALK we adopt NAT-PT/SIIT and DSTM/DSTM options and as implementation environment we use Linux Kernel 2.4.18 and Netfilter framework. Software modules implemented in Linux kernel was ported to hardware box using Motorola MPC 8260 processor. The transition mechanisms used in 6TALK are the ones predicted to be used in initial transition step to IPv6.

• Journal of Korea Water Resources Association
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• v.44 no.5
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• pp.389-406
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• 2011

The objective of this study is to examine the climate change impact assessment on Korean water resources considering the uncertainties of Global Climate Models (GCMs) and hydrological models. The 3 different emission scenarios (A2, A1B, B1) and 13 GCMs' results are used to consider the uncertainties of the emission scenario and GCM, while PRMS, SWAT, and SLURP models are employed to consider the effects of hydrological model structures and potential evapotranspiration (PET) computation methods. The 312 ensemble results are provided to 109 mid-size sub-basins over South Korean and Gaussian kernel density functions obtained from their ensemble results are suggested with the ensemble mean and their variabilities of the results. It shows that the summer and winter runoffs are expected to be increased and spring runoff to be decreased for the future 3 periods relative to past 30-year reference period. It also provides that annual average runoff increased over all sub-basins, but the increases in the northern basins including Han River basin are greater than those in the southern basins. Due to the reason that the increase in annual average runoff is mainly caused by the increase in summer runoff and consequently the seasonal runoff variations according to climate change would be severe, the climate change impact on Korean water resources could intensify the difficulties to water resources conservation and management. On the other hand, as regards to the uncertainties, the highest and lowest ones are in winter and summer seasons, respectively.