• Journal of Aerospace System Engineering
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• v.16 no.3
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• pp.105-114
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• 2022

The purpose of this study was to present a conceptual design of the 6U micro-satellite system for optical image of 3 m GSD. An optical camera system with a payload of 3 m GSD image was designed and optimized. The optical system has a diameter of Ø78 mm, length 250 mm, and 1400 mm focal length. The requirement and constraints were configured for the 6U micro-satellite bus system with the payload. Satisfying the requirement and constraints, the subsystems of the 6U bus were designed such as attitude and orbit control, propulsion, command and data handling, electrical power, communication, structures and mechanisms, and thermal control subsystem. The mass budget, power budget, and communication link budget were also confirmed for the 6U micro-satellite comprising the optical payload and the subsystems of bus. To take optical images, a mission operation concept is proposed for the 6U micro-satellite in a low-Earth orbit. A constellation comprising many 6U micro-satellites studied in this paper, can provide with various data for reconnaissance and disaster tracking.

• Journal of KIISE
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• v.44 no.5
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• pp.476-485
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• 2017

The tactical operation centers of future anti-aircraft missile systems provide the environment for the research on future air threats, tactical information, integrated battlefield environment creation and management, engagement control and command and control algorithms. To develop the key functional elements of integrated battlefield situation creation and processing and tactical operation automation processing operations, battery/battalion tactical operation control and reconfiguration design software are required. Therefore, the algorithm software of each function and the tactical operation display software and link software for interworking between equipment were developed as reconfigurable through a data-centric design. In this paper, a tactical operation display framework that can be reconfigured on the operation display of the tactical operations according to the battery/battalion is introduced. This tactical operation display framework was used to develop a common data model design for the reconfigurable structure of multi-role tactical operations with battery / battalion and mission views, and a display configuration tool that provides a tactical operation display framework for view development was also developed using the MVC pattern. If the tactical operation display framework is used, it will be possible to reuse the view design through the common base structure, and a view that can be reconfigured easily and quickly will also be developed.

• Journal of Periodontal and Implant Science
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• v.45 no.2
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• pp.56-61
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• 2015

Purpose: The aim of this study was to evaluate the effectiveness of powered toothbrushes for plaque control in patients with peri-implant mucositis, in comparison with manual toothbrushes. Methods: This randomized, prospective, controlled, clinical parallel study compared the efficacy of manual and powered toothbrushes for plaque control in implant restorations. Patients with bleeding on probing, no residual pocket depth (as indicated by a pocket probing depth ${\geq}5mm$), and no radiological peri-implant bone loss were eligible for this study. Patients were requested to complete a questionnaire describing their oral hygiene habits. The duration and frequency of tooth brushing were recorded by subjects in order to assess their compliance. Clinical parameters, including the modified plaque index (mPI), the modified sulcus bleeding index (mSBI), and clinical photographs (buccal and lingual views) were recorded at baseline and at one-month and two-month follow-up visits. Results: Statistically significant differences between patients who used manual toothbrushes and those who used powered toothbrushes were found regarding the frequency of tooth brushing per day and the duration of brushing at one-month and two-month follow-up visits, while no statistically significant differences were found relating to other oral hygiene habits. A statistically significant difference in patient compliance for tooth brushing was found at one month, while no difference was found at two months. Statistically significant decreases in the mPI and the mSBI were observed in both groups from baseline to the one- and two-month follow-ups. The overall reduction of these parameters was not significantly different between the two groups, except for mPI reduction between baseline and one month of follow-up. Conclusions: Sonic-powered toothbrushes may be a useful device for plaque control in patients with peri-implant mucositis.

• Journal of Satellite, Information and Communications
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• v.6 no.1
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• pp.37-44
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• 2011

COMS(Chollian) satellite which was launched on June 26, 2010 has three payloads for Ka-band communications, geostationary ocean color imaging and meteorological imaging. In order to make efficient use of the geostationary satellite, a concept of mission operations has been considered from the beginning of the satellite ground control system development. COMS satellite mission operations are classified by daily, weekly, monthly, and seasonal operations. Daily satellite operations include mission planning, command planning and transmission, telemetry processing and analysis, ranging and orbit determination, ephemeris and event prediction, and wheel off-loading set point parameter calculation. As a weekly operation, North-South station keeping maneuver and East-West station keeping maneuver should be performed on Tuesday and Thursday, respectively. Spacecraft oscillator updating parameter should be calculated and uploaded once a month. Eclipse operations should be performed during a vernal equinox and autumnal equinox season. In this paper, operational validations of the major functions in COMS SGCS are presented for the first three month of in-orbit test operations. All of the major functions have been successfully verified and the COMS SGCS will be used for the mission operations of the COMS satellite for 7 years of mission life time and even more.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.5
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• pp.2897-2901
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• 2013

Gastric cancer is the second most common cause of cancer-related deaths in the world. Although certain dietary factors and lifestyles have been suggested to be associated with gastric carcinogenesis, there have been few investigations focusing on rural areas. A case-control study was therefore carried out to investigate the risk factors of gastric cardia cancer (GCC) in rural areas of Linzhou. A total of 470 newly diagnosed cases of GCC and 470 healthy controls were included. Face-to-face interviews were conducted, using a uniform questionnaire containing questions on demographics, per capita income, living habits, dietary habits and family history of tumors. The relationship between putative risk factors and GCC was assessed by odds ratios (OR) and their 95% confidence intervals (95%CI) derived from conditional logistic regression model by the COXREG command using SPSS 12.00. Multivariate logistic regression analysis was used to evaluate simultaneously the effects of multiple factors and other potential confounding factors. Multivariate logistic analysis showed that smoking (OR=1.939, 95%CI:1.097-3.426), alcohol drinking (OR=2.360, 95%CI: 1.292-4.311), hot food consumption (OR=2.034, 95%CI: 1.507-2.745), fast eating (OR=1.616, 95%CI: 1.171-2.230), mouldy food (OR=4.564, 95%CI: 2.682-7.767), leftover food (OR=1.881. 95%CI: 1.324-2.671), and family history of tumor (OR=2.831, 95%CI: 1.588-5.050) were risk factors for GCC. High per capita income (OR=0.709, 95%CI: 0.533-0.942), high education level (OR=0.354, 95%CI: 0.163-0.765), consumption of fresh fruits (OR=0.186, 95%CI: 0.111-0.311) and vegetables (OR=0.243, 95%CI: 0.142-0.415), and high BMI (OR=0.367, 95%CI: 0.242-0.557) were protective factors for GCC. Our data indicate that unhealthy lifestyle and dietary habits might be important contributors to GCC in this population.

• The Journal of the Acoustical Society of Korea
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• v.19 no.3
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• pp.51-56
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• 2000

Is this paper, we studied on the automatic speech control system in real-time windows environment using voice recognition. The applied reference pattern is the variable DMS model which is proposed to fasten execution speed and the one-stage DP algorithm using this model is used for recognition algorithm. The recognition vocabulary set is composed of control command words which are frequently used in windows environment. In this paper, an automatic speech period detection algorithm which is for on-line voice processing in windows environment is implemented. The variable DMS model which applies variable number of section in consideration of duration of the input signal is proposed. Sometimes, unnecessary recognition target word are generated. therefore model is reconstructed in on-line to handle this efficiently. The Perceptual Linear Predictive analysis method which generate feature vector from extracted feature of voice is applied. According to the experiment result, but recognition speech is fastened in the proposed model because of small loud of calculation. The multi-speaker-independent recognition rate and the multi-speaker-dependent recognition rate is 99.08% and 99.39% respectively. In the noisy environment the recognition rate is 96.25%.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.5
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• pp.571-578
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• 2014

The boundaries of ROK maritime jurisdictional area remains unclear as two Koreas failed to draw clear maritime boundaries at the armistice agreement and there are no clear maritime boundaries with China and Japan. After the Korean War, the United Nations Command established the northern limit line(NLL) as well as the area of operations(AO) to enforce the DPRK's compliance with the armistice agreement and has been controlling all of the maritime and air activities in the region. ROK also has been controlling the passage of DPRK vessels in the area. Within the AO, third nation vessels have freedom of navigation, Yet, due to the division followed by the Korean War, ROK classifies DPRK as a hostile state and unique controling system is applied to DPRK vessels. Since the establishment of the AO, many changes have been occurring such as adoption of the UN Convention on the Law of the Sea(UNCLOS) and two Koreas' joining the UN. Also, there are continuous inter-Korean conflicts. Therefore, the geographical span of the AO needs to be reconsidered. Furthermore, a legal measure which ensures ROKN vessel's functional capability of controling DPRK vessels must be introduced. This thesis examines post-Korean War DPRK vessel control system in the Korean peninsula as well as how it should be improved.

• Journal of the Korea Society of Computer and Information
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• v.17 no.12
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• pp.31-39
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• 2012

In this paper, we propose a microprocessor-based automatic voltage regulator(AVR) to reduce consumers' electric energy consumption and to help controlling peak demanding power. Hybrid Switching Automatic Voltage Regulator (HS-AVR) consist of a toroidal core, several tap control switches, display and command control parts. The coil forms an autotransformer which has a serial main winding and four parallel auxiliary windings. It controls the output voltage by changing the combination of the coils and the switches. Relays are adopted as the link switches of the coils to minimize the loss. To make connecting and disconnecting time accurate, relays of the circuit have parallel TRIACs. A software phase locked loop(PLL) has been used to synchronize the timings of the switches to the voltage waveform. The software PLL informs the input voltage zero-crossing and positive/negative peak timing. The traditional voltage transformers and AVRs have a disadvantage of having a large mandatory capacity to accommodate maximum inrush current to avoid the switch contact damage. But we propose a suitable AVR for every purpose in smart grid with reduced size and increased efficiency.

• Journal of Practical Engineering Education
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• v.10 no.1
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• pp.17-24
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• 2018

Through the design and production of works for the third semester as a major unit, It is proposed the process of satisfying the graduation standards with the design and production process of the drone which can be applied to various mobile environments. Using the shape of Ring Propeller, it is made to be able to play both the role of generating lift as a propeller and the role of a wheel that touches the ground through the surface of the rim. In addition, the Servo Motor is used to convert the drive shaft of the motor to the correct angle according to the command. Then, based on the idea, the 3D printing is implemented to confirm the result of the configuration, and the circuit for driving the propulsion is designed and manufactured. As a result, the conversion of the desired propulsion system during air navigation and operation failed due to the weight increase of the propellant. It is confirmed that the size of the thrust and the tolerance limit of the ring propeller are the errors. Through these processes, it has been recognized to have experience of creative thinking and cooperation through engineering approach and comprehensive design, and confirmed to satisfy the graduation criteria by writing an engineering paper on the result.

• Information Systems Review
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• v.18 no.4
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• pp.69-88
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• 2016

Nowadays, organizations have adopted Smart Work to efficiently manage tasks, such as electronic document approval, customer management, and site inspection, without spatial-temporal constraints. Smartphones, which are commonly used in Smart Work, enable individuals to perform their jobs anytime and anywhere, thus blurring the boundary between work and non-work. To solve the problem of blurred work/non-work boundaries, a construct of self-control and affective factors needs to be considered because business style is changed from command to autonomy in the Smart Work context. Moreover, employees can convey their emotions easily over smartphones. Recent marketing studies have analyzed consumers' behavior based on the combination of cognitive, affective, and behavioral components, and researchers of information systems are also interested in these factors. However, previous research has some limitations, such as not classifying factors into cognitive, affective, and behavioral as well as not covering all three factors. Therefore, we explore the roles of cognitive, affective, and behavioral components in emotional exhaustion and education performance, and conduct a survey on undergraduate and graduate students, who are the major users of smartphones. Findings show that when individuals improve their cognitive capability (self-control) and usage experience (smartphone communication and internet usage), they can decrease emotional exhaustion and increase education performance. In the role of affective capability, increasing education performance is partially accepted. These results imply that organizations should not focus on controlling the usage of smartphones but on promoting appropriate smartphone usage.