• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.17 no.1 s.104
• /
• pp.74-80
• /
• 2006

This paper presents the characteristics of electromagnetic field uniformity in a reverberation chamber that can be used alternatively for the analysis, test and evaluation of electromagnetic interference and immunity. The dual-band diffuser, which can be used at two different frequency bands in a reverberation chamber, is applied, and it is made of two different single-band Schroeder's Quadratic Residue Diffusers. The FDTD method is used to analyze the field characteristics. Compared with single-band diffuser, the dual-band diffuser shows the improvement in not only expansion of test frequency band but also in characteristics of the field uniformity, polarity, power efficiency, and tolerance. Therefore, the reverberation chamber with the dual-band diffuser is a better facility, for the analysis and measurement of electromagnetic interference and immunity, than the reverberation chamber with a single-band diffuser.

• Journal of the Microelectronics and Packaging Society
• /
• v.13 no.2 s.39
• /
• pp.1-7
• /
• 2006

In this paper, warpage magnitude and shape of printed-circuit board in case that properties of core and thickness of solder resist are varied are investigated. The cause of warpage is coefficient of thermal expansion differences of stacked materials. Therefore, we need small difference of coefficient of thermal expansion that laminated material, and need to decrease asymmetric of top side and bottom side in structure shape. Also, we can control occurrence of warpage heightening hardness of core in laminated material. Composite material that make core are exploited in connection with the structural bending twisting coupling resulting from directional properties of fiber reinforced composite materials and from ply stacking sequence. If we use such characteristic, we can control warpage with change of material properties. In this paper, warpage of two layer stacked chip scale package is investigated, and evaluate improvement result using an experiment and finite element method tool.

• Journal of the Korean Geotechnical Society
• /
• v.20 no.7
• /
• pp.99-105
• /
• 2004

When a saturated clay is sampled from a borehole in an undisturbed manner, the exerted negative pore water pressure restricts the volume expansion. The vertical and horizontal stresses to which the clay was subjected in the ground are smaller and larger than this isotropically confining stress equivalent to the mean principal stress in the ground, respectively. Therefore the sample expands vertically and shrinks laterally under an undrained condition. In the ordinary consolidation test, the sample thus deformed is trimmed to fit the inside of the consolidometer ring. Thus, the specimen generates larger consolidation displacement due to confining larger horizontal stress when in-situ effective pressure is loaded. The specimen does not reproduce the in-situ consolidation behavior, In this paper, considering sample deformation, the test specimen is made to expand laterally to fit the inside of the ring in the undrained manner when the in-situ effective pressure is loaded. And applicability of this proposed test procedure was verified; results from the conventional consolidation test procedure are also discussed.

• Proceedings of the KIEE Conference
• /
• 1996.07c
• /
• pp.2004-2006
• /
• 1996

A thermally driven polysilicon micro actuator has been fabricated using surface micromachining techniques. It consists of P-doped polysilicon as a structural layer and TEOS (tetracthylorthosilicate) as a sacrificial layer. The polysilicon was annealed for the relaxation of residual stress which is the main cause to its deformation such as bending and buckling. And the newly developed HF VPE (vapor phase etching) process was also used as an effective release method for the elimination of sacrificial TEOS layer. The thickneas of polysilicon is $2{\mu}m$ and the lengths of active and passive polysilicon cantilevers are $500{\mu}m$ and $260{\mu}m$, respectively. The actuation is incurred by die thermal expansion due to the current flow in the active polysilicon cantilever, which motion is amplified by lever mechanism. The moving distance of polysilicon micro actuator was experimentally conformed as large as $21{\mu}m$ at the input voltage level of 10V and 50Hz square wave. The actuating characteristics are investigated by simulating the phenomena of heat transfer and thermal expansion in the polysilicon layer. The displacement of actuator is analyzed to be proportional to the square of input voltage. These micro actuator technology can be utilized for the fabrication of MEMS (microelectromechanical system) such as micro relay, which requires large displacement or contact force but relatively slow response.

• Journal of the Korean Society of Costume
• /
• v.61 no.6
• /
• pp.131-145
• /
• 2011

The purpose of this study is to provide preliminary data on strategies to create a domestic prestige brand based on Korean traditional designs. This study also deals with how to promote this brand around the world. The two points mentioned above will be accomplished by examining the characteristics of the brand '3.1 Phillip Lim' which succeeded in both design and marketing during a short period of time. The method of the study will be followed. Firstly, the basic design and philosophical background of Phillip Lim was investigated, after reviewing the global luxury market and current status of overseas expansion of Korean designers through paper study and antecedent workups. Secondly, for the practical stage, design characteristics and marketing strategies were reviewed with the collections of '3.1 Phillip Lim'. Three factors found in '3.1 Phillip Lim's design success are as follows: First, practical and simple designs using fabrics of high quality. Second, handcraft elements and interesting details that differentiates his design identity. Third, femininity expressed in the feminine silhouette and color. The marketing elements that made '3.1 Phillip Lim' as a successful brand are: First, differentiated positioning as a luxurious contemporary brand. Second, brand promotion through various collaborations. Third, the gradual expansion of women's, men's, kids' apparel to accessory, lingerie and the stable flagship stores. Thus, '3.1 Phillip Lim' has combined modern and classic styles using high quality fabrics and practical designs with unique details. Through it's differentiated marketing strategy targeting New York's market, which prefers popular 'luxury contemporary brand's rather than high-end luxury brands, this brand's creativity and commercial aspects contributed to make '3.1 Phillip Lim' into a luxury brand that represents New York fashion. Korean designers who seek to enter the global fashion industry should consider applying Korean traditional designs on global designs to make favorable products and localize these products according to regional characteristics.

• The Journal of Korean Institute for Practical Engineering Education
• /
• v.2 no.2
• /
• pp.55-60
• /
• 2010

We usually encounter Electro-magnetics phenomenons and only feel some part of that, but it is hard to feel it visually. Moreover understanding physically and quantitatively is not a easy work. These electrostatic field theory, magnetostatic field theory and interchange magnetic field theory combined with electromagnetic field are formulated experimentally and theoretically by James Clerk Maxwell in 1873. Electromagnetic field takes electro-magnetic phenomenons as a expansion of formula originated in Maxwell equations. Since this is based on expansion of formula, it is hard to understand for many students not only middle school and high school students learning it at the first time but also college students studying physics as a elementary class and even majors in electromagnetic field. The program is developed as a visual aid to cope with these problems, and even to deal with complex problem to estimate solution using numerical method.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.2
• /
• pp.690-696
• /
• 2016

Search engines that rely on morphological matching of user query and web document content do not support individual interests. This research proposes a personalized web search scheme that returns the results that reflect the users' query intent and personal preferences. The performance of the personalized search depends on using an effective user profiling strategy to accurately capture the users' personal interests. In this study, the user profiles are the databases of topic words and customized weights based on the recent user queries and the frequency of topic words in click history. To determine the precise meaning of ambiguous queries and topic words, this strategy uses WordNet to calculate the semantic relatedness to words in the user profile. The experiments were conducted by installing a query expansion and re-ranking modules on the general web search systems. The results showed that this method has 92% precision and 82% recall in the top 10 search results, proving the enhanced performance.

• Journal of Digital Convergence
• /
• v.18 no.2
• /
• pp.1-12
• /
• 2020

This study aimed to select and evaluate policy priorities for the expansion of public and semi-public systems for coastwise passenger transport services. For research methodology, the Consistent Fuzzy Preference Relations (CFPR) method was used to effectively extract expert knowledge. First, the result of the analysis on policy tasks for expanding the semi-public system for coastwise passenger transport services showed that "the establishment of public transportation fare system" was the most important task at 0.160. Second, "conversion of the subsidiary routes to a public system by the central government" was ranked next at the importance of 0.136. The factor named "support through proper allocation of budgets between national and local governments" are ranked third (0.119). The results of this study have practical implications in that it proposed the policy priorities for the expansion of the public semi-public systems for coastwise passenger transport services.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.35 no.9
• /
• pp.1085-1098
• /
• 2011

In the $21^{st}$ century, technology is a tool for the expansion of the five senses and physical ability that works as an element for posthuman identity. This study analyzes and theorizes on the characteristics of the posthuman body in fashion illustration. The method of this study analyzes documentaries about posthuman and fashion illustration. The results are as follow. Posthuman body types are classed as hybrid body, plastic surgery body, and digital body. The characteristics of the posthuman body are categorized as ultra- functional prosthetic, mythical undifferentiated, radical plastic surgery type and post-physical digitization type. The ultra-functional prosthetic type shows a restored body and upgraded functional body through a machine hybrid, cyborg suit and mannequin hybrid. It is a break from classical gender identity to form a nerve sense extension that displays physical and abstract power. The mythical undifferentiated type shows a therianthropic form, parts of an animal body, radical skin and gender bending. It represents the return to an undifferentiated world, the desire of a powerful being and the possibility of radical transformation. The radical plastic surgery type shows a photomontage of an ideal body, transgendered body, grotesque body marking, absence of partial or overall face organ and the expansion of abnormal body organs. It represents the expression of narcissism, unconscious desire, fantasy, fear and suggests an alternative ideality, sexual attachment and ambiguous gender identity. The post-physical digitization type shows an imperfect form or duplicated ego image through the omission of the body silhouette or detailed form, fragmented image using net, representative self like optical illusion using typography, an imperfect vague silhouette and immaterial body outline through the use of virtual light. It represents the lack of desire, narcissism, fluidity in a virtual space, the continued creation of a new self, ambiguous gender identity and the liberation of environment, sex, and race. Likewise, the posthuman in fashion illustration shows the absence of a species boundary, destruction of classical gender identity, a new personality and virtual self image.

• International Journal of Highway Engineering
• /
• v.14 no.3
• /
• pp.1-7
• /
• 2012

The purpose of this study was to review application of ASTM C 1260 for cement matrix with flyash and lithium nitrate using reactive aggregate. The experimental program included the accelerated mortar bar test (AMBT: ASTM C 1260) for the slate which was evaluated as reactive aggregate by ASTM C 1260 at the previous study. The cement, which was substituted by 10, 20, 30% flyash containing less than 10% CaO, could control ASR expansion. From the experiment applying lithium nitrate to control ASR, the mortar bar containing lithium nitrate showed more than 0.1% expansion at 14 days. This is probably due to dissolution of lithium nitrate in NaOH solution during test periods. Thus, it is necessary to adopt another test method to verify the control effect of lithium nitrate against alkali-silica reaction.