• Journal of Astronomy and Space Sciences
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• v.33 no.4
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• pp.323-333
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• 2016

In this study, the uncertainty requirements for orbit, attitude, and burn performance were estimated and analyzed for the execution of the $1^{st}$ lunar orbit insertion (LOI) maneuver of the Korea Pathfinder Lunar Orbiter (KPLO) mission. During the early design phase of the system, associate analysis is an essential design factor as the $1^{st}$ LOI maneuver is the largest burn that utilizes the onboard propulsion system; the success of the lunar capture is directly affected by the performance achieved. For the analysis, the spacecraft is assumed to have already approached the periselene with a hyperbolic arrival trajectory around the moon. In addition, diverse arrival conditions and mission constraints were considered, such as varying periselene approach velocity, altitude, and orbital period of the capture orbit after execution of the $1^{st}$ LOI maneuver. The current analysis assumed an impulsive LOI maneuver, and two-body equations of motion were adapted to simplify the problem for a preliminary analysis. Monte Carlo simulations were performed for the statistical analysis to analyze diverse uncertainties that might arise at the moment when the maneuver is executed. As a result, three major requirements were analyzed and estimated for the early design phase. First, the minimum requirements were estimated for the burn performance to be captured around the moon. Second, the requirements for orbit, attitude, and maneuver burn performances were simultaneously estimated and analyzed to maintain the $1^{st}$ elliptical orbit achieved around the moon within the specified orbital period. Finally, the dispersion requirements on the B-plane aiming at target points to meet the target insertion goal were analyzed and can be utilized as reference target guidelines for a mid-course correction (MCC) maneuver during the transfer. More detailed system requirements for the KPLO mission, particularly for the spacecraft bus itself and for the flight dynamics subsystem at the ground control center, are expected to be prepared and established based on the current results, including a contingency trajectory design plan.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.12
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• pp.1682-1688
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• 2017

In modern society, the number of industrial customers using equipment sensitive particularly to voltage sags is rapidly increasing. As voltage sags can cause loss of information as well as false operation of the control device, it results in the vast economic damage in industrial processes. One way to mitigate voltage sags in the sensitive loads is the installation of distributed generation (DGs) on the periphery of these loads. In addition, renewable energy sources are currently in the spot light as the potential solution for the energy crisis and environmental issues. In particular, wind power generation which is connected to a grid is rising rapidly because it is energy efficient and also economically feasible compared to other renewable energy sources. On the basis of the above information, in this paper, with Wind Turbine Generators (WTGs) installed nearby the sensitive load, the analysis of the mitigating effect comparison by types of WTGs is performed using voltage sag assessment on the IEEE-30 bus test system. That is, the areas of vulnerability according to types of WTGs are expected to be different by how much reactive power is produced or consumed as WTG reactive power capability is related to the types of WTGs. Using the concept of 'Vulnerable area' with the failure rate for buses and lines, the annual number of voltage sags at the sensitive load with the installation of WTGs per type is studied. This research will be anticipated to be useful data when determining the interconnection of wind power generation in the power system with the consideration of voltage sags.

• Journal of Korean Society of Transportation
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• v.30 no.2
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• pp.53-65
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• 2012

This study was performed to investigate the currents status of the sexual assaults on women public transportation users and to provide solutions in order to provide safe transportation services to women. Data was collected through in-depth interviews with career women in Gyeonggi-do. The main purpose of the interview was to understand their experiences about sexual assaults while using public transport and to investigate the extent to which their experiences affected their transportation-related behaviors. The effects of various related transport policies on women behaviors were also analyzed by estimating structural equation models. The results showed that among them, CCTV, accessible warning bells, and more police presence seemed to be more effective, but that woman-only sections were not as effective as others in reducing the number of crimes. The results implied that individual subjective norms and their perceived behavioral control, behavior intention were important factors. Based on these results, we recommended additional policies more effective in sexual crime reduction.

• Journal of Wetlands Research
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• v.17 no.2
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• pp.176-183
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• 2015

This study is aimed at deducting the evaluation standard of the walking tour trail and evaluating the real condition of trail facilities and operation & management. On the basis of the research on the walking tour, this study deducted the evaluation index of the trail facilities and administrative control, and divided it into visit resources, visit facilities and trail operation-management. This study selected the course of high use satisfaction among the Ganghwa Nadeul-gil section, and evaluated the real condition of Ganghwa Nadeul-gil trail by classifying the route as nature-oriented trail and culture-oriented trail. In case of nature-oriented trail, it's necessary to discover living culture resources of the village linked with the trail, and to develop amenities using bus stations and supermarket. In case of culture-oriented trail, it's required that economic regeneration plan should be arranged using the declining facilities.

• The KIPS Transactions:PartA
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• v.15A no.6
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• pp.317-324
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• 2008

In this paper, we propose a system which easily controls the existing serially connected multi-channel speakers in a general personal computer by using a USB(Universal Serial Bus) interface. The personal computer as a host of the USB interface analyzes a sound source and sends audio data in a real-time fashion by the use of the isochronous transmission, one of four transmission methods provided by the USB interface. In addition, a channel is assigned by means of the bulk transmission, one of four transmission methods provided by the USB interface. Transmitted data from the USB host are sent to each speaker through compression and packet generation process. Each speaker detects corresponding digital data and regenerates audio signals through DAC(Digital-to-Analog Converter). A user can easily select a sound source file and a channel by the use of a GUI environment in a personal computer.

• Journal of IKEEE
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• v.25 no.2
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• pp.291-301
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• 2021

OPC UA at the control and field level does not provide enough performance to replace the field bus. The OPC Foundation aims for a real-time and connection-less mechanism, and has added the OPC UA publish-subscribe model, a new specification that supports broker functions such as MQTT and AMQP, as the OPC UA Part 14 standard. This paper is about a gateway for interoperability between OPC UA publisher with the addition of OPC UA Part14 standard and DDS subscribers. Raspberry Pi 4 is used for the gateway proposed in this paper, and OpenDDS, an open source, is used for DDS. OPC UA publish-subscribe module used A-Open62541 publish-subscribe module, which additionally implements functions not provided by the corresponding source based on Open62541 publish-subscribe open source.

• Journal of Advanced Navigation Technology
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• v.26 no.5
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• pp.358-364
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• 2022

The Inter Communication System for avionics is in charge of processing all voice signals that internal calls between Pilot and Co-pilot, internal calls between Pilots and Crews, external calls through communication equipment such as Ultra/Very High Frequency Receiver/Transmitter(U/VHF RT), audio signal monitoring for navigation and mission equipment such as VHF Omnidirectional Range/Instrument Landing System(VOR/ILS), Tactical Air Navigation(TACAN), audio signal output for voice recording to Flight Data Recorder(FDR) and Data Transfer System(DTS), and warning/caution audio signal generate about the status and threat of aircraft. Because Inter Communication System for avionics is sensitive to noise in the case of analog audio signals, a redundant design that can protect audio signal from electromagnetic noise inside/outside of aircraft is required for the mission of pilots and crews. In this paper, Normal/Back-up operation mode and redundancy design plan based on digital method for the redundancy of the digital Inter Communication System for avionics and manufacturing, verification results are described.

• Parasites, Hosts and Diseases
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• v.21 no.2
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• pp.257-264
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• 1983

In order to obtain more specific antigenic preparation for the diagnosis of human paragonlmiasis, crude saline extract of whole worm (=PwWWE), secretory.excretory components (PwSEC) and secretion-excretion-free somatic extract (PwSM) of 12 week-old ParagoninBus westermani were filtrated through Sephadex G-200 gel column. The adult Paragonimus worms were obtained from expevimentally infected doge. A total of 11 antigenic solutions was Iyophilised or diluted to adjust protein content of 1mg/ml. To evaluate the antigenicity of crude antigens and fractions, micro-ELISA was done with the sera from P westermani in(ected cases, C. sinensis infected cases and non-infected control cases to detect Paragonimus specific IgG antibody. The results were as follows: 1. When the PwWWE was filtrated through Sephadex G-200 gel, it was separated into three fractions; PwWWE Fr. 1, PwWWE Fr. 2 and PwWWE Fr. 3. The percentage of protein content was 28.0%, 21.6% and 50.4% respectively. The PwSM was also. separated into three fractions; PwSM Fr. 1, PwSM Fr. 2, PwSM Fr. 3. and their percentage of protein content was 41.3%, 38.6% and 20.1%. However, the PwSEC showed different fractionation pattern; i.e. fraction 1 (=PwSEC Fr.1) and 3 (PwSEC Fr. 3) without fraction 2. The percentage of protein content was 14.0% in PwSEC Fr. 1 and 86.0% in PwSEC Fr. 3. 2. When the antigenicity of each Paragonimus crude antigen and fractionated antigen was evaluated for specific IgG aritibody by micro-ELISA in 10 human paragonimiasis sera, PwSEC Fr, 1 was the most potent antigen showing the mean absorbance 1.98. The PwWWE Fr. 1, PwSEC, PwWWE were next to that: their mean absorbance were 1.72, 1.38 and 0.83 respectively. The antigenicity of fractions 2 and 3 was much weaker in binding specific IgG antibody. 3. When the antigens were reacted in micro-ELISA with 10 human clonorchiasis sera, most antigens showed weak reactivity. Each fraction 1 of crude antigens reacted higher than other fractions or crude antigens; the mean absorbance was 0.17 in fraction 1, but in others the absorbances were about 0.06. 4. With non-infected control sera, the result of micro-RLISA revealed almost same pattern with those of the clonorchiasis sera. From the above results, it became apparent that PwWWE Fr. 1, especially PwSEC Fr. 1 was the most potent antigen reacted with Paragonisfaus specific IgG antibody.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.699-707
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• 2016

This paper proposes a low-complexity central processing unit (CPU) that is suitable for deeply embedded systems, including Internet of things (IoT) applications. The core features a 16-bit instruction set architecture (ISA) that leads to high code density, as well as a multicycle architecture with a counter-based control unit and adder sharing that lead to a small hardware area. A co-processor, instruction cache, AMBA bus, internal SRAM, external memory, on-chip debugger (OCD), and peripheral I/Os are placed around the core to make a system-on-a-chip (SoC) platform. This platform is based on a modified Harvard architecture to facilitate memory access by reducing the number of access clock cycles. The SoC platform and CPU were simulated and verified at the C and the assembly levels, and FPGA prototyping with integrated logic analysis was carried out. The CPU was synthesized at the ASIC front-end gate netlist level using a $0.18{\mu}m$ digital CMOS technology with 1.8V supply, resulting in a gate count of merely 7700 at a 50MHz clock speed. The SoC platform was embedded in an FPGA on a miniature board and applied to deeply embedded IoT applications.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.2
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• pp.89-96
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• 2009

As increasing the number of digital control devices installed on aircrafts and their transmission speed, various digital data buses have been introduced to provide reliable and high-speed characteristics. These characteristics of avionics data bus are highly related on the fault-tolerant performance which can make minimize jitter and loss during data transfer. In this paper, we concerned about a new traffic shaping scheme for increasing the reliability of Avionics Full Duplex Switched Ethernet (AFDX) systems based on ARINC 664 standard. We note that the conventional AFDX with a single regulator per virtual link system may produce aggregated traffics as the number of virtual links increasing. The aggregated traffic results in large jitters among frames. To remedy for the jitter and loss of data, we propose a dual regulator scheme for the AFDX system. The purpose of the additional regulator is to additionally regulate aggregated traffics from a number of per virtual link regulators. Using NS-2 simulator, we show that the proposed scheme provides a better performance than the single regulator one. It is worthwhile note that the proposed AFDX with Dual Regulator scheme can be employed to not only aircraft networks but other QoS sensitive networks for robot and industrial control systems.