• International Journal of Aeronautical and Space Sciences
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• v.8 no.1
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• pp.10-20
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• 2007

For spacecraft attitude control, reaction wheel (RW) steering laws with more than three wheels for three-axis attitude control can be derived by using a control allocation (CA) approach.1-2 The CA technique deals with a problem of distributing a given control demand to available sets of actuators.3-4 There are many references for CA with applications to aerospace systems. For spacecraft, the control torque command for three body-fixed reference frames can be constructed by a combination of multiple wheels, usually four-wheel pyramid sets. Multi-wheel configurations can be exploited to satisfy a body-axis control torque requirement while satisfying objectives such as minimum control energy.1-2 In general, the reaction wheel steering laws determine required torque command for each wheel in the form of matrix pseudo-inverse. In general, the attitude control command is generated in the form of a feedback control. The spacecraft body angular rate measured by gyros is used to estimate angular displacement also.⁵ Combination of the body angular rate and attitude parameters such as quaternion and MRPs(Modified Rodrigues Parameters) is typically used in synthesizing the control command which should be produced by RWs.¹ The attitude sensor signals are usually corrupted by noise; gyros tend to contain errors such as drift and random noise. The attitude determination system can estimate such errors, and provide best true signals for feedback control.⁶ Even if the attitude determination system, for instance, sophisticated algorithm such as the EKF(Extended Kalman Filter) algorithm⁶, can eliminate the errors efficiently, it is quite probable that the control command still contains noise sources. The noise and/or other high frequency components in the control command would cause the wheel speed to change in an undesirable manner. The closed-loop system, governed by the feedback control law, is also directly affected by the noise due to imperfect sensor characteristics. The noise components in the sensor signal should be mitigated so that the control command is isolated from the noise effect. This can be done by adding a filter to the sensor output or preventing rapid change in the control command. Dynamic control allocation(DCA), recently studied by Härkegård, is to distribute the control command in the sense of dynamics⁴: the allocation is made over a certain time interval, not a fixed time instant. The dynamic behavior of the control command is taken into account in the course of distributing the control command. Not only the control command requirement, but also variation of the control command over a sampling interval is included in the performance criterion to be optimized. The result is a control command in the form of a finite difference equation over the given time interval.⁴ It results in a filter dynamics by taking the previous control command into account for the synthesis of current control command. Stability of the proposed dynamic control allocation (CA) approach was proved to ensure the control command is bounded at the steady-state. In this study, we extended the results presented in Ref. 4 by adding a two-step dynamic CA term in deriving the control allocation law. Also, the strict equality constraint, between the virtual and actual control inputs, is relaxed in order to construct control command with a smooth profile. The proposed DCA technique is applied to a spacecraft attitude control problem. The sensor noise and/or irregular signals, which are existent in most of spacecraft attitude sensors, can be handled effectively by the proposed approach.

• Korean journal of applied entomology
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• v.7
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• pp.69-75
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• 1969

These studies aimed to investigating the pathogenicity of Fusarium isolates from the wilted cucur bitaceous plants and the pathogenicity of 24 isolates to cucumber, oriental cantaloup, oriental pickling melon, sponge gourd. muskmelon and watermelon were as follows. 1) The isolates from wilted watermelon and melon severely and one of the isolates was slightly pathogenicon oriental pickling melon or oriental cantaloup. 2) The isolates from wilted cucumber were four types. some of the isolates were severely pathogenic on cucumber and infected oriental cantaloup. oriental pickling melon and melon. Some of the isolates were not pathogenic or slightly pathogenic on cucumber. but these were severely pathogenic on oriental pickling melon. One of the isolates was severely pathogenic on oriental cantaloup oriental pickling melon and melon, but no pathogenic on cucumber and one of the isolates was also severely pathogenic on oriental cantaloup. oriental pickling melon and melon and moderatly pathogenic' on water melon. 3) The isolates from wilted oriental cantaloup were four types some of the isolates infected oriental cantaloup, oriental pickling melon and melon severely and some of the isolates were pathogenic on oriental cantaloup. oriental pickling melon. melon and watermelon. One of the isolates, was slightly pathogenic on oriental pickling melon and melon but one of the isolates was highly pathogenic on melon and infected watermelon slightly. 4) Wilt Fusarium of the cucurbitaceous plants could divide into the group of wilt Fusarium of watermelon, cucumber and muskmelon according to the pathogenicity but it will have to rearrange to one form species from several form species of wilt Fusarium of the cucurbitaceous plants and ought to divide to races according to pathogenicity on severely fixed differential varieties which selected from the cucurbitaceous plants. because of the degree of pathognicity and host range are not surely fixed between isolates of wilt Fusarium of the cucurbitaceous plants tested.

• Journal of Technologic Dentistry
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• v.36 no.4
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• pp.277-296
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• 2014

Purpose: This study intends to set standard for organizing the curriculum of short-term dental technicians and the change of job environment, as well as the knowledge & training, by identifying the importance and actual job performance of dental technicians following job analysis in the university education of Dept. of Dental Laboratory Technology, and furthermore to foster junior executives to cope with modernization and globalization. Methods: The tools used in this study are based on the job analysis of research report suggested by National Health Personnel Licensing Examination Board(Lee Gyu-seon, 2011), and it consists of general characteristic 7 items. Every competence duty was measured through Likert 5 point gauging, and internal consistency through Cronbach's Alpha. The competence importance of entire questionnaire was .984 and its performance was .874, reflecting considerably high level, and in terms of each competence duty, high credibility was proved and high internal consistency was verified with competence importance ranging from the minimum .655 to the maximum .966 and its performance ranging from the minimum .677 to the maximum .993. Results: Competence importance and its performance in each duty on the job analysis of dental technicians were measured. In competence importance in each duty, the highest was "checking design order form"(average, 4.52), followed by "selling dental prosthesis"(average 4.49), "making removable orthodontic appliance"(average, 4.48), "open managing dental laboratory"(average, 4.46) in order. However, "making complete denture" was found the lowest(average, 4.23), with importance of all competence dutys was considerably high level. In the performance of its competence duty, "checking design order form"(average, 4.04) was found to be the most importance competence, followed by "making conservative restoration"(average, 4.00), "making porcelain"(average 3.98), "checking working cast"(average, 3.90) in order. However it was found out that "making fixed orthodontic appliance"(average, 3.12) was the lowest, and the importance of all competence dutys was quite high level. Conclusion: The duties of dental technicians consist of 13 kinds, in total, and it was found out that "checking design order form"(average, 4.52) was the most important in the competence importance and job performance. In particular, it was revealed that there was a great difference between the competence importance and its performance in the order of "selling dental prosthesis", "open managing dental laboratory", "making removable orthodontic appliance", "making CAD/CAM prosthesis", and then "making fixed orthodontic appliance".

• International Journal of Contents
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• v.16 no.2
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• pp.65-77
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• 2020

The purpose of this study was to examine the impacts of the audience and vlog creator's self-disclosure, media synchronicity (immediacy of feedback, variety of symbol set), as well as content authenticity on the intimacy between the vlogger and the audience and continuance intention of the audience. The participants of the online survey were young Chinese females, instructed to practice their routine of watching vlog and the fixed vlog channels. By the interpersonal process of intimacy model and media synchronicity theory, the results of the structural equation modeling revealed that self-disclosure (audience's disclosure) and partner responsiveness (vlogger's disclosure) form the experience of intimacy in interactions. Also, the quick immediacy of feedback, rich symbol set, and content authenticity positively impacted intimacy development. Meanwhile, intimacy enables the audience to form a continuous viewing behavior. We expect the results of this study will provide more insight into the relationship between the audience and the producer in online video content. In terms of the personal media influencers and MCN companies, this study is also suggests strategic implications.

• The Journal of Korean Academy of Prosthodontics
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• v.31 no.1
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• pp.151-162
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• 1993

The author installed $3.75mm\times10mm$ $Br{\aa}nrmark$ osseointegrated implants and $3.5mm\times8mm$ I.T.I. hollow screw implants(Benefit) as a free standing abutment to replace lower left and right molars of 44-year-old female patient. Form the foregoing procedure, the author obtained the following results. 1. Free-standing $Br{\aa}nrmark$ and I.T.I. Hollow screw implants(Benefit) could be used to replace molars effectively without reduction of adjacent natural teeth, 2. Rotation of occlusal gold screw of $Br{\aa}nrmark$ implants was observed under occlusal force. 3. Adjustment of height of I.T.I. abutments was necessary in the mandibular second molar because of the limited occlusal clearance. 4. Form the oral examination, patient comments, panoramic and periapical radiographs, there were no pain, gingival imflammation and mobility, but slight reduction of alveolar bone level was shown around both implant systems. 5. Patient comments were comfortable on both systems. but the patient complained about economic problem of $Br{\aa}nrmark$ system and long treatment treatment time of both systems.

• Korean Journal of Materials Research
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• v.15 no.5
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• pp.293-300
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• 2005

ZnO:Li epilayers were synthesized on sapphire substrates by the pulesd laser deposition (PLD) after the surface of the ZnO:Li sintered pellet was irradiated by the ArF (193 nm) excimer laser. The growth temperature was fixed at $400^{\circ}C$. The crystalline structure of epilayers was investigated by the photoluminescence (PL) and double crystal X-ray diffraction (DCXD). The carrier density and mobility of epilayers measured by van der Pauw-Hall method are $2.69\times10cm^{-3}$ and $52.137cm^2/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of epilayers obtained from the absorption spectra is well described by the Varshni's relation, $E_g(T)=3.5128eV{\cdot}(9.51\times10^{-4}eV/K)T^2/(T+280K)$. After the as-grown ZnO:Li epilayer was annealed in Zn atmospheres, oxygen and vaccum the origin of point defects of ZnO:Li has been investigated by PL at 10 K. The Peaks of native defects of $V_{zn},\;V_o,\;Zn_{int},\;and\;O_{int}$ showned on PL spectrum are classified as a donors or accepters type. We confirm that $ZnO:Li/Al_2O_3$ in vacuum do not form the native defects because ZnO:Li epilayers in vacuum existe in the form of stable bonds.

• Sijohaknonchong
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• v.21
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• pp.271-284
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• 2004

'Haedonggayo(해동가요)' has 82 sijo poems written by Lee, Jeong bo, including his 20 saslsijo. In this paper, 3 saslsijo are analyzed. Their themes are 'performing a sexual act', 'sensual appetites', 'temptation'. Result from analyzing these 3 saslsijo was compared to other saslsijo. The purpose of this comparison is to comfirm the characteristics of his three works. Four consequences are obtained. First. materials of these three works are not just arranged in a row but set systemically. Second, designed meaning is showed concretely. Third, these three works have everything that is needed to represent designed meaning. Forth, designed maeaning has fixed form.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.258-267
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• 2003

Recently inside nano liposome particles or nano-emulsions which contain tough-melting physiology activity materials or the coefficient of low organism utilization promote the coefficient of organism utilization, so this part has been studied a lot because they can absorb selectly cosmetics, specially physiology activity materials, into the skin. Also, in particle size, cells interstitial lipid interval are 30~50nm, so nano-emulsions that the size is similar to 30~50 nm are made to study for absorbing quickly into the skin. And transparent skin which contains oils in common skin lotion dosage form has become the center of public interest. The used nano-emulsions in this study were unsaturated lecithin/co-surfactant! ethanol/ oil / water. And polysorbate 20/ polysorbate 80/ Dicetyl phosphate/hydrogenated .caster oil/ isoceteth-20/SLS were used in co-surfactant. The used oils were cyclomethicone and caprylic/capric triglyceride. The manufacturing process was that microfluidizer was fixed in 1000bar and transit times were changed from 1 to 10 times. From transparency and particle size, the transparency sequence was SLS> polysorbate 20= polysorbate 80> isoceteth-20> dicetyl phosphate >hydrogenated caster oil and the particle size was small. Specially cyclomethicone nano-emulsions, when we made unsaturated lecithin /SLS /ethanol/water/cyclomethicone, cyclomethicone 5％ was good for transparency. And 20％ of this was used for making transparent skin toner in common skin dosage form.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.11
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• pp.1666-1671
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• 1989

A novel switched-capacitor circuit for interfacing capacitive microtransducers with a digital system is developed based on the dual-slope integration. It consists of a differential integrator and a comparator. Driven by the teo phase clock, the circuit first senses the capacitance difference between the transducer and the reference capacitor in the form of charge, and accumulates it into the feedback capabitor of the integrator for a fixed period of time. The resulant accumulated charge is next extracted by the known reference charge until the integrator output voltage refurns to zero. The length of time required for the integrator output to return to zero, as measured by the number of clock cycle gated into a counter is proportional to the capacitance difference, averaged over the integration period. The whole operation is insensitive to the reference voltage and the capacitor values involved in the circuit, Thus the proposed circuit permits an accurate differental capacitance measurement. An error analysis has showh that the resolution as high as 8 bits can be expected by realizing the circuit in a monolithic MOS IC form. Besides the accuracy, it features the small device count integrable onto a small chip area. The circuit is thus particularly suitadble for the on-chip interface.

• The Research Journal of the Costume Culture
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• v.12 no.6 s.53
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• pp.918-932
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• 2004

Fashion is a product of form expressing the socio-cultural mood and aesthetic value of an age. Owing to development of the mass media and diversification of arts under the influence of post-modernism in the 20th century, fashion has been more briskly expressed to be presented to the people. With such basic conceptions in mind, this study was aimed at reviewing the fashion photography as visual medium. To this end, visual narrative techniques were analyzed and thereupon, Philip-Lorca diCorcia's fashion photography was examined. This study reviews such visual narrative techniques by dividing into visual and non-visual elements and thereby, examines the three-fold aspects of fashion photography expressions : Representative Level, Ground Level and Context Level. Also this study focuses on Philip-Lorca diCorcia's fashion photography in 'W magazine' which features portfolio form. This study analyzed the visual narratives shown in fashion photography and thereby, expand in diverse ways the fixed images of the conventional fashion photography commercials featuring beautiful models and exquisite costumes, and additionally, determined that fashion photography must be a kind of expression tool which could express not only the simple fashion but also the socio-psychological elements inherent in fashion.