• Smart Structures and Systems
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• v.19 no.5
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• pp.487-497
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• 2017

Semi-active devices use the building's own motion to produce resistive forces and are thus strictly dissipative and require little power. Devices that independently control the binary open/closed valve state can enable novel device hysteresis loops that were not previously possible. However, some device hysteresis loops cannot be obtained without active analog valve control allowing slower, controlled release of stored energy, and is presents an ongoing limitation in obtaining the full range of possibilities offered by these devices. This in silico study develops a proportional-derivative feedback control law using a validated nonlinear device model to track an ideal diamond-shaped force-displacement response profile using active analog valve control. It is validated by comparison to the ideal shape for both sinusoidal and random seismic input motions. Structural application specific spectral analysis compares the performance for the non-linear, actively controlled case to those obtained with an ideal, linear model to validate that the potential performance will be retained when considering realistic nonlinear behaviour and the designed valve control approach. Results show tracking of the device force-displacement loop to within 3-5% of the desired ideal curve. Valve delay, rather than control law design, is the primary limiting factor, and analysis indicates a ratio of valve delay to structural period must be 1/10 or smaller to ensure adequate tracking, relating valve performance to structural period and overall device performance under control. Overall, the results show that active analog feedback control of energy release in these devices can significantly increase the range of resetable, valve-controlled semi-active device performance and hysteresis loops, in turn increasing their performance envelop and application space.

• Journal of the Korean Mathematical Society
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• v.31 no.4
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• pp.619-628
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• 1994

The multiplicity theory initiated by C. Chevalley was the one with respect to ideals generated by a system of parameters of a local ring containing a field [3] and [4]. Samuel generalized the definition to primary ideals belonging the maximal ideal of a local ring which contains a field by a device which used the Hilbert characteristic function [9]. Furthermore Samuel defined multiplicity also in local rings which contain no field [10].

• Korean Journal of Mathematics
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• v.21 no.3
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• pp.319-323
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• 2013

Let D be a principal ideal domain, X be an indeterminate over D, D[X] be the polynomial ring over D, and $R_n=D[X]/(X^n)$ for an integer $n{\geq}1$. Clearly, $R_n$ is a commutative Noetherian ring with identity, and hence each nonzero nonunit of $R_n$ can be written as a finite product of irreducible elements. In this paper, we show that every irreducible element of $R_n$ is a primary element, and thus every nonunit element of $R_n$ can be written as a finite product of primary elements.

• Journal of Korean Neurosurgical Society
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• v.43 no.4
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• pp.201-204
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• 2008

Angiosarcoma of the brain, either primary or metastatic is extremely rare. Moreover, angiosarcoma metastazing to the brain is also highly unlike to occur when comparing with metastases to the other organs. Thus, an ideal treatment strategy has not been established. A 67-year-old man with past surgical history of a scalp angiosarcoma underwent surgical resection of intracranial invasion. Because of wide scalp flap excision and resultant poor vascularity of the scalp flap, additional radiation was not provided. Because adjuvant therapy is impossible due to poor scalp condition, more careful but ample resection of the primary lesion is essential to conduct initial operation.

• Journal of The Korean Digital Architecture Interior Association
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• v.9 no.3
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• pp.77-83
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• 2009

Van Doesburg founded the magazine De Stijl with Mondrian in 1917. De Stijl movement was influenced by Cubist painting as well as by the mysticism and the ideas about ideal geometric forms in the neoplatonic philosophy. De Stijl proposed ultimate simplicity and abstraction by using only straight horizontal and vertical lines and rectangular forms. Furthermore, their formal vocabulary was limited to the primary colours, red, yellow, and blue, and the three primary values, black, white, and grey. The works avoided symmetry and attained aesthetic balance by the use of opposition. Vertical and horizontal lines are positioned in layers or planes that do not intersect, thereby allowing each element to exist independently and unobstructed by other elements In 1924 their different concepts about space and time were split between Van Doesburg and Mondrian. Van Doesburg launched a new concept for his art, Elementarism, which was characterized by the diagonal lines and rivaled with Mondrian's Neo-Plasticism. The works of De Stijl would influence the Bauhaus style and the international style of architecture.

• The Research Journal of the Costume Culture
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• v.4 no.1
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• pp.15-28
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• 1996

This study is concerned with the prohibition of False Hair(加笙) and a primary factor in Lee Dynasty. Assuming that the trend of simplification in false hair is closely related to the idea of practical science to be the social and ideal background of those times, we researched. The results are as follows: Constant discussions and prohibitions against false hair were designed to differentiate between classes but to discard a variety. Goge(高笙) came to be a big problem during the reign of king Sung-Jong(成宗) and after on arguemt for the usage of false hair was in vogue king Young-Jo(英祖) and Jung-Jo(正祖). Finally, the wearing of Hooge(後笙) came to be a national regulation in manners and customs, and also brought the realization of prohibition against the usage of false hair. It is believed that the performance and the effect of the prohibition against the usage of false hair have a close relation with the idea of practical science.

• Journal of the Korean Ceramic Society
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• v.35 no.10
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• pp.1049-1054
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• 1998

In order to fabricate ideal powders new processing is necessary in which the solute atoms in solution ra-pidly move to mix each other to the degree of molecular level the viscosity of solution should be low not to effect the moving of solute atoms and the powders could be directly obtained as crystalline. Supercritical fluid is defined as condensed gas sated up to its critical pressure and temperature. In this paper su-percritical fluid methods were studied as a new ceramic processing of powder preparation. The crystalline powders of TiO2 which are useful for electronic ceramic materials were fabricated by hydrolysis of titanium (IV) ethoxide using ethanol as a supercritical fluid at the condition of 270$\pm$3$^{\circ}C$, 7.3 MPa for 2hr. The cry stalline anatase powders could be directly obtained and its primary particle size was 20 min.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.11C
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• pp.1119-1126
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• 2007

In this paper, we examine the scheme that the CR (Cognitive Radio) user can coexist with primary user with obeying the concept of interference temperature proposed by FCC. Regarding to the capability of classifying the signals of primary user after the spectrum sensing, the interference temperature model can be discriminated by the ideal and generalized ones. And then, about each model, it can optimize the bandwidth and transmit power with satisfying predetermined capacity of CR user. Especially, it has been considered to allocate to CR user not to interfere to primary users for proper coexistence in conventional interference temperature multiple access technique, proposed by T. Clancy, but this paper proposes the scheme that considering QoS of not only primary users, but also CR user. The hill-climbing algorithm is employed to produce the bandwidth and transmit power subject to satisfying the required capacity.

• Smart Structures and Systems
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• v.17 no.2
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• pp.231-256
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• 2016

This study concerns the derivation of optimum tuning formulas for a passive Tuned Mass Damper (TMD) device, for the case of benchmark ideal excitations acting on a single-degree-of-freedom (SDOF) damped primary structure. The free TMD parameters are tuned first through a non-linear gradient-based optimisation algorithm, for the case of harmonic or white noise excitations, acting either as force on the SDOF primary structure or as base acceleration. The achieved optimum TMD parameters are successively interpolated according to appropriate analytical fitting proposals, by non-linear least squares, in order to produce simple and effective TMD tuning formulas. In particular, two fitting models are presented. The main proposal is composed of a simple polynomial relationship, refined within the fitting process, and constitutes the optimum choice. A second model refers to proper modifications of literature formulas for the case of an undamped primary structure. The results in terms of final (interpolated) optimum TMD parameters and of device effectiveness in reducing the structural dynamic response are finally displayed and discussed in detail, showing the wide and ready-to-use validity of the proposed optimisation procedure and achieved tuning formulas. Several post-tuning trials have been carried out as well on SDOF and MDOF shear-type frame buildings, by confirming the effective benefit provided by the proposed optimum TMD.

• Korean Journal of Bronchoesophagology
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• v.4 no.1
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• pp.27-34
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• 1998

Despite improvement in respiratory care, including use of low pressure and high volume cuffed tubes, tracheal stenosis remains a serious complication after a long-term tracheal intubation and tracheostomy. In such patients, tracheal resection and primary anastomosis is still considered ideal therapeutic modality. Between 1989 and 1997, we performed tracheal resections with end-to-end anastomosis on 14 patients with no operative mortality and some morbidity. Tracheal stenosis was caused by tracheostomy in nine patients, by endotracheal intubation in three patients and by thyroid carcinoma in two patients. The length of stenosis was various from 2cm to 4.5cm. All patient underwent segmental tracheal resection and primary anastomosis(14 patients) and additional procedures were cricoid cartilage reconstruction(2 patients), suprahyoid laryngeal release(3patients), carinal release technique(2 patients) and arytenoidectomy(2 patients). We have nine complications: granulona at anastomosis site in four patients, vocal cord palsy in two patients and restenosis, pneumonia, skin necrosis in each of those patients. The granuloma was removed by bronchoscopic forceps(4 patients). Vocal cord palsy was treated by arytenoidectorny(2 patients), restenosis by T-tube insertion, pneumonia by antibiotics and skin necrosis was treated by skin graft. We reviews our expenence of clinical features of tracheal stenosis and surgical treatment by tracheal one-to-end anastomosis with additional procedures to avoid postoperative complications for sucessful results.