• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.10
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• pp.89-96
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• 2003

In this paper, a CCSDS(Consultative Committee for Space Data Systems) telecommand(TC) decryptor for the security of geostationary communications satellite was implemented. For the confidentiality of CCSDS TC datalink security, Option-A which implements the security services below the transfer sublayer was selected. Also CFB(Cipher Feedback) operation mode of DES(Data Encryption Standard) was used for the encryption of 56-bit data bits in 64-bit codeblock. To verify Decryptor function, the DES CFB logic implemented on A54SX32 FPGA(Field Programmable Gate Array) was integrated with interface and control logics in a PCB(Printed Circuit Board). Using a function test PC, the encrypted codeblocks were generated, transferred into the decryptor, decrypted, and the decrypted codeblocks were transmitted to the function test PC, and then compared with the source codeblocks. Through LED(Light Emitting Diode) ON operation by driving the relay related to Op-code decoded and the comparison between the codeblock output waveforms measured and those simulated, the telecommand decryptor function was verified.

• Korean Institute of Interior Design Journal
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• v.27 no.2
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• pp.77-85
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• 2018

The number of household living alone including young single adults has gradually increased. The purpose of this study is to examine the demand on housing options, additional space, shared space, community facilities, housing service for young adults living alone including college students. A total of 180 questionnaire were collected and analyzed. For housing location, commuting distance is the most important feature and amenities are the second important feature. For additional space, there is a significant difference between male and female single residents. Female residents want to install dress room most while male adults want to have a study room. For the shared house option, single adults concerns housing fee and living cost most. However, female adults concern safety and security issues much more than male ones do. The degree of preference to community facilities varies between male and female single residents. The findings suggest more differentiated approaches are needed for alternative housing options for male and female residents.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.38
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• pp.28.1-28.6
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• 2016

Backgrounds: Insufficient intermaxillary space is caused by non-restoration following tooth extraction in the past, and this involves eruption of the opposing teeth and changes of the arch structure. Such cases are difficult just by a simple prosthetic approach, and diversified treatment plans should be established. Among these, posterior maxillary segmental osteotomy (PMSO) is an efficient treatment option than extraction of opposing teeth as it surgically repositions multiple erupted teeth and alveolar bone. PMSO can preserve the natural teeth; therefore, it is being regarded as a treatment method which can improve insufficient intermaxillary space significantly. Case presentation: In this case report, the first patient received PMSO in order to place an implant in the mandibular edentulous space after decreased vertical dimension is restored, and the second patient received PMSO along with orthodontic treatment to obtain the intermaxillary space and balance the interarch molar width. Conclusion: PMSO is the treatment of choice when occlusion is compromised in the presence of decreased vertical dimension or arch length discrepancy.

• Journal of Astronomy and Space Sciences
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• v.37 no.1
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• pp.1-9
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• 2020

Frozen orbit is an attractive option for orbital design owing to its characteristics (its argument of pericenter and eccentricity are kept constant on an average). Solar sails are attractive solutions for massive and expensive missions. However, the solar radiation pressure effect represents an additional force on the solar sail that may greatly affect its orbital behavior in the long run. Thus, this force must be included as a perturbation force in the dynamical model for more accuracy. This study shows the calculations of initial conditions for a lunar solar sail frozen orbit. The disturbing function of the problem was developed to include the lunar gravitational field that is characterized by uneven mass distribution, third body perturbation, and the effect of solar radiation. An averaging technique was used to reduce the dynamical problem to a long period system. Lagrange planetary equations were utilized to formulate the rate of change of the argument of pericenter and eccentricity. Using the reduced system, frozen orbits for the Moon sail orbiter were constructed. The resulting frozen orbits are shown by two 3Dsurface (semi-major, eccentricity, inclination) figures. To simplify the analysis, we showed inclination-eccentricity contours for different values of semi-major axis, argument of pericenter, and values of sail lightness number.

• Journal of Korean Institute of Industrial Engineers
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• v.21 no.2
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• pp.195-206
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• 1995

Higher utilization of warehouse space can be achieved by using automated mobile racking systems. Therefore, those systems may be employed for factories or distribution centers as a good option of increasing the storage capacity. In this paper, travel-time models are developed to estimate the average performance of the system assuming randomized storage. Expected travel times are determined for both single- and dual-command cycles. Two extreme input/output-point locations are considered. Some numerical results obtained from the models are given.

• Journal of Astronomy and Space Sciences
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• v.38 no.2
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• pp.105-117
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• 2021

In this study, a preliminary trajectory design is conducted for a conceptual spacecraft mission to a near-Earth asteroid (NEA) (99942) Apophis, which is expected to pass by Earth merely 32,000 km from the Earth's surface in 2029. This close approach event will provide us with a unique opportunity to study changes induced in asteroids during close approaches to massive bodies, as well as the general properties of NEAs. The conceptual mission is set to arrive at and rendezvous with Apophis in 2028 for an advanced study of the asteroid, and some near-optimal (in terms of fuel consumption) trajectories under this mission architecture are to be investigated using a global optimization algorithm called monotonic basin hopping. It is shown that trajectories with a single swing-by from Venus or Earth, or even simpler ones without gravity assist, are the most feasible. In addition, launch opportunities in 2029 yield another possible strategy of leaving Earth around the 2029 close approach event and simply following the asteroid thereafter, which may be an alternative fuel-efficient option that can be adopted if advanced studies of Apophis are not required.

• Journal of Korean Society of Transportation
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• v.30 no.6
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• pp.13-26
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• 2012

In this study, factors influencing the parking policy compliance (i.e. levying a garage option on car buyers) were identified, and then, were applied to the theory of planned behavior. To find out the influence of factors and their path, the study built a parking policy compliance model using structural equation modeling. The independent variables such as attitude, subjective norm, perceived behavioral control had positive effects on the parameter describing the efforts to secure his garage, but the parameter impact on the dependent variable was not significant. In the end, the independent variables affected the dependent variable was not significant. The perceived behavioral control utilizing regulations had positive effects on the parking policy compliance behavior, but past behavior such as street parking and prowling to find a free parking space had a negative effect on parking policy compliance behavior.

• The KIPS Transactions:PartC
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• v.12C no.7 s.103
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• pp.1039-1046
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• 2005

TCP SACK is the unique mechanism to reflect the situation of sink's sequence space, some TCP variants and proposals can perform in conjunction with SACK mechanism for achieving optimal performance. By definition of RFC 2018, however, each contiguous block of data queued at the data receiver is defined in the SACK option by two 32-bit unsigned integers in network byte order. Since TCP Options field has a 40-byte maximum length, when error bursts now, we note that the available option space may not be sufficient to report all blocks present in the receiver's queue and lead to unnecessarily force the TCP sender to retransmit Packets that have actually been received by TCP sink. For overcoming this restriction, in this thesis, a new solution named 'one-byte offset based SACK mechanism' is designed to further improve the performance or TCP SACK and prevent those unwanted retransmissions. The results or both theory analysis and simulation also show that his proposed scheme operates simply and more effectively than the other existing schemes by means of the least bytes and most robust mechanism to the high packet error rates often seen in networks environment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.7
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• pp.616-622
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• 2012

In this paper, we examined the problems of the flare operation of tactic maneuvering flight of fighter aircraft with 150GL center external fuel tank and proposed the possible solution of it's operation. The damage scope of horizontal fin of fuel tank and flare trajectory when the flare ejected from the maneuvering aircraft were analyzed by the wind tunnel test and the numerical analysis. We investigated the two different option to avoid the damage of fin; i) the adjustment of flare dispenser angle and ii) the change of horizontal fin's shape. For the considering of practical operation of present system, we chose the second option. We estimated the drop safety of external fuel tank with redesigned fin by the wind tunnel experiments.

• Journal of the Korean Society of Clothing and Textiles
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• v.18 no.1
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• pp.43-56
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• 1994

The Purpose of this study was to utilize of CAD System in pattern making process for women's apparel. The automation by the use of CAD System provides the higher accuracy and efficiency in pattern making process. AccuMark 300 System was used. for .this study. The results from this study were as follows . 1. New size spec chart and grading pitch chart were developed based on the data analysis and fitting tests for female college students. 2. New jacket block was developed based on the torso length sloper 3. Automatic grading of jacket block have been developed by creation and modification of grading rules of block pattern. 4. Pattern Design Systyem(P/D/S) were enabled to be constructed directly form a block pattern by modifications to existing styled pattern. 5. Original master pattern was generated by P/D/S menu option. 6. Production pattem added seam allowance, notchs was generated by P/D/S menu option. 7 Interative maker making process have enabled to save a wide range of time and space. 8. Measurement of garment by P/D/S measuring tools is to utilize in garment costing, quality control.