• 전기학회논문지
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• 제63권2호
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• pp.211-216
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• 2014

Construction of power plants and T&D facilities is so difficult because of the civil complaints and the additional cost according to the concerning field conditions. Therefore, various researches and methods have been considered to get solutions in the demand side and energy storage systems have been in the spotlight because of the various functions such as peak shaving, load shifting, and power system stabilizing, and so on. Residential small size batteries are considered in this paper and the economic analysis is carried out to evaluate the reasonable subsidy levels for the deployment of energy storage systems. Various economic parties are considered to find reasonable subsidy level comparing each other, which parties consist of utilities, participants and non-participants in general. The evaluation is based on California Standard Practice Test and the results are able to be used as subsidy guidelines.

• 한국지역지리학회지
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• 제17권2호
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• pp.141-149
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• 2011

사자평 고산습지는 유역분지 및 기반암의 특성과 화전의 영향을 받아 형성되었다. 사자평 유역분지는 출구가 좁고, 기반양은 많은 암설을 생산하여 사면 아래로 공급한다. 그리고 화전을 위하여 삼림을 제거함으로써 표토의 세립물질이 사전천의 하상에 퇴적되어, 시전천의 유로 주변에 고산습지가 형성되었다 사자평의 습원에는 도로를 따라 우곡이 형성되었는데, 우곡은 습원으로 공급되는 사력물질과 통류의 공급을 차단함으로써 습원을 건조화 시킨다. 이를 방지하기 위해서는 배수로의 수위를 기반암 풍화층의 높이까지 높여 습원으로 통류가흐를 수 있도록 하여야 하며, 배수로의 모양을 자연스러운 불규칙한 형태로 조정하여야 하고 시전천의 하상에 인위적인 방해물을 적치하여 시전천의 하상이 낮아지는 것을 방지하여야 한다.

• Ocean and Polar Research
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• 제35권4호
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• pp.351-353
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• 2013

Until recently, Pacific equatorial tropical island states were subject of only very limited interest by scientists, government officials, industry and policy makers of Korea. And, comprehensive information and data on these island regions is not very detailed to help better understand their social backgrounds as well as their natural environment. However, these island regions are now in the middle of diplomatic tug-of-war among super powers as well as becoming nucleus of various science-based ocean issues including marine biodiversity, shifting ecosystem, global environmental change including sea level rise and ocean acidification, fisheries, etc. Therefore, rising political and scientific importance of these areas call for better understanding of these regions, in social aspects as well as natural scientific knowledge of the region. To be provocatively prepared to more actively role in these regions, "A study on Establishing Research Infrastructures in the Tropical Pacific" has been supported during 2012-2013 as a mission-oriented in-house project of the KIOST. This project aims to provide various research infrastructure for Pacific island states, to reinforce cooperation with these nations, and to enhance Korea's national prestige. This special issue contains 10 research articles based on the studies conducted in 2012~2013.

• Journal of the Optical Society of Korea
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• 제20권1호
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• pp.42-54
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• 2016

A hybrid color and grayscale images encryption scheme based on the quaternion Hartley transform (QHT), the two-dimensional (2D) logistic map, the double random phase encoding (DRPE) in gyrator transform (GT) domain and the three-step phase-shifting interferometry (PSI) is presented. First, we propose a new color image processing tool termed as the quaternion Hartley transform, and we develop an efficient method to calculate the QHT of a quaternion matrix. In the presented encryption scheme, the original color and grayscale images are represented by quaternion algebra and processed holistically in a vector manner using QHT. To enhance the security level, a 2D logistic map-based scrambling technique is designed to permute the complex amplitude, which is formed by the components of the QHT-transformed original images. Subsequently, the scrambled data is encoded by the GT-based DRPE system. For the convenience of storage and transmission, the resulting encrypted signal is recorded as the real-valued interferograms using three-step PSI. The parameters of the scrambling method, the GT orders and the two random phase masks form the keys for decryption of the secret images. Simulation results demonstrate that the proposed scheme has high security level and certain robustness against data loss, noise disturbance and some attacks such as chosen plaintext attack.

• 대한의용생체공학회:의공학회지
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• 제19권4호
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• pp.417-422
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• 1998

본 연구는 대퇴의족착용자의 정적중립상태 및 자유보행시에 단단부와 소케의 경계에 작용하는 압력 분포를 측정하였다. 정적중립상태에서는 단단부의 외측과 내측면과 후면에서 압력집중현상이 나타나고, 자유보행시는 이러한 압력집중이 보행중에 일정한 형태로 이동함을 알 수 있었다. 최대 소켓압력은 중간입각기나 발뒤축들림기에 외측, 내측 앞쪽, 후면에서 나타나고 있고, 소켓과 단단부 사이의 상태를 확인하는 방법중 하나로 소켓 압력 측정을 사용할 수가 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.673-676
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• 2003

In this paper, we designed the embedded system used for wireless LAN communication. Embedded system kernel is made from general linux kernel 2.4.18 by applying the ARM patch (2.4.18-rmk7) and the SA1100 patch(2.4.18-rmk7), then porting board level suitable to target system. The SA-1110 PCMCIA interface provides controls for one PCMCIA card slot with a PSKTSEL pin for support of a second slot. The embedded system requires external logic to complete the PCMCIA socket interface. For dual-voltage support, level shifting buffers are required for all SA-1110 input signals. Hot insertion capability requires that each socket be electrically isolated from each other, and from the remainder of the memory system. embedded system is for socket services approaching PCMCIA socket, detecting number of sockets, sensing insertion and removal, and applying power. It also provides interface with Card services. Embedded system supports Host driver for lucent chips that is installed orinoco driver cross compiled. The meaning can say that is doing wireless LAN communication through wireless LAN in imbedded system.

• Current Optics and Photonics
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• 제7권4호
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• pp.387-397
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• 2023

Tooth surface shape error is an important parameter in gear accuracy evaluation. When tooth surface shape error is measured by laser interferometry, the gear interferogram is highly distorted and the gray level distribution is not uniform. Therefore, it is important for gear interferometry to extract the foreground region from the gear interference fringe image directly and accurately. This paper presents an approach for foreground extraction in gear interference images by leveraging the sinusoidal variation characteristics shown by the interference fringes. A gray level mask with an adaptive threshold is established to capture the relevant features, while a local variance evaluation function is employed to analyze the fluctuation state of the interference image and derive a repair mask. By combining these masks, the foreground region is directly extracted. Comparative evaluations using qualitative and quantitative assessment methods are performed to compare the proposed algorithm with both reference results and traditional approaches. The experimental findings reveal a remarkable degree of matching between the algorithm and the reference results. As a result, this method shows great potential for widespread application in the foreground extraction of gear interference images.

• ETRI Journal
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• 제46권2호
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• pp.227-237
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• 2024

This study proposes a novel, conditionally applied neural network technique to reduce the overall peak-to-average power ratio (PAPR) of an orthogonal frequency division multiplexing (OFDM) system while maintaining an acceptable bit error rate (BER) level. The main purpose of the proposed scheme is to adjust only those subcarriers whose peaks exceed a given threshold. In this respect, the developed C-ANN algorithm suppresses only the peaks of the targeted subcarriers by slightly shifting the locations of their corresponding frequency samples without affecting their phase orientations. In turn, this achieves a reasonable system performance by sustaining a tolerable BER. For practical reasons and to cover a wide range of application scenarios, the threshold for the subcarrier peaks was chosen to be proportional to the saturation level of the nonlinear power amplifier used to pass the generated OFDM blocks. Consequently, the optimal values of the factor controlling the peak threshold were obtained that satisfy both reasonable PAPR reduction and acceptable BER levels. Furthermore, the proposed system does not require a recovery process at the receiver, thus making the computational process less complex. The simulation results show that the proposed system model performed satisfactorily, attaining both low PAPR and BER for specific application settings using comparatively fewer computations.

• 대한전자공학회논문지SD
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• 제43권6호
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• pp.9-17
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• 2006

SoC(System-On-Chip) 시스템에서 초 저전력 시스템을 구현하기 위한 dynamic voltage and frequency scaling (DVFS)알고리즘에 사용될 시스템 버스의 다중 코어 전압 레벨을 생성해주는 새로운 다계층(multi-level) 코어 전압용 high-speed level up/down Shifter 회로를 제안한다. 이 회로는 내부 회로군과 외부 회로군 사이에서 서로 다른 전압레벨을 조정 접속하는 I/O용 level up/down shifter interface 회로로도 동시에 사용된다. 제안하는 회로는 인터페이스 접속에서 불가피하게 발생하는 속도감쇄와 Duty Ratio 불안정 문제를 최소화하는 장점을 갖고 있다. 본 회로는 500MHz의 입력 주파수에서 $0.6V\sim1.6V$의 다중 코어 전압을 각 IP들에서 사용되는 전압레벨로, 또는 그 반대의 동작으로 서로 Up/Down 하도록 설계하였다 그리고 제안하는 I/O 용 회로의 level up shifter는 500MHz의 입력 주파수에서 내부 코어 용 level up shifter의 출력전압인 1.6V를 I/O 전압인 1.8V, 2.5V, 3.3V로 전압레벨을 상승 하도록 설계하였으며, level down shifter는 반대의 동작으로 1Ghz의 입력 주파수에서 동작하도록 설계하였다. 시뮬레이션 및 결과는 $0.35{\mu}m$ CMOS Process, $0.13{\mu}m$ IBM CMOS Process 와 65nm CMOS model 변수를 이용한 Hspice를 통하여 검증하였다. 또한, 제안하는 회로의 지연시간 및 파워소모 분석과 동작 주파수에 비례한 출력 전압의 Duty ratio 왜곡에 대한 연구도 하였다.

• 한국환경과학회지
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• 제29권1호
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• pp.1-13
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• 2020

Recently, a heavy rainfall with high spatial variation occurred frequently in the Korean Peninsula. The meteorological event that occurred in Busan on 3 May 2016 is characterized by heavy rain in a limited area. In order to clarify the reason of large spatial variation associated with mountain height and location of low level jet, several numerical experiments were carried out using the dynamic meteorological Weather Research and Forecasting (WRF) model. In this case study, the raised topography of Mount Geumjeong increased a barrier effect and air uplifting due to topographic forcing on the windward side. As a result, wind speed reduced and precipitation increased. In contrast, on the downwind side, the wind speed was slightly faster and since the total amount of water vapor is limited, the precipitation on the downwind side reduced. Numerical experiments on shifting the location of the lower jet demonstrated that if the lower jet is close to the mountain, its core becomes higher due to the effect of friction. Additionally, the water vapor convergence around the mountain increased and eventually the precipitation also increased in the area near the mountain. Hence, the location information of the lower jet is an important factor for accurately predicting precipitation.