• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.1
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• pp.1-7
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• 2014

An impeller is difficult to machine due to the complex, overlapping and twisted shapes that form the blades of an impeller. Therefore, most CAM software companies have developed a CAM module for manufacturing an impeller in addition to their CAM software. However, it is not easy for inexperienced users to machine impellers. The purpose of this paper is to outline the development of an automatic CAM module for the manufacturing of an impeller (E-ICAM) which is based on visual basic language and which uses a CATIA graphical environment in order to simplify the machining of impellers. The automatic CAM module generates a tool path and proposes the recommended cutting condition according to the stock and tool material. In addition, it includes a post-processor for five-axis control machining. Therefore, a user can easily machine impellers using this automation module. There are two types of impellers: the closed and open types. The closed-type impeller consists of the body and cover parts. To combine these two parts, it is necessary to create tap holes on the shroud of the body. Therefore, in the study, a drilling CAM program for a closed-type impeller is developed and manufactured by creating NC data from the developed drilling program. After manufacturing the test specimen, its compatibility was verified.

• Journal of the Korean Society of Costume
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• v.58 no.1
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• pp.9-16
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• 2008

Six of the Imdang tombs containing remains with imprints of ancient fabrics and textiles were investigated. Within the tombs, a total of 120 pieces of imprinted fabrics and textiles were investigated, all of which belongs to $5{\sim}6C$ Shilla period. All of the hemp textiles examined exhibited similar characteristics found in ancient hemp textiles: they were woven by plain weave technique with s-twist threads. The examined silk could be categorized into plain woven silk, cho, and double woven brocade, all of them made with non-twisted threads and degummed silk. The density of the plain woven silk ranged from 39 threads to 144 threads. Cho was also found, which showed similar characteristics to those of Gaya and Bakjae tombs. One piece of 2/1 twill weave on plain ground and 12 pieces of double woven brocade were found and their average density was $97.4{\times}33.4/cm$ with denser warp than weft. The various thickness of the threads were observed in the examined plain braid. The silk with twining technique showed thicker warp than weft. This is similar to the techniques of fabrics found in the King Muryeoung's Tomb of the Bakjae period. Fabrics with the purple-like color were observed in the some of the double woven brocades and also on the plain woven silk imprinted on the remains. The purple-like color was revealed to be purple with a tint of violet. The two tombs from which the imprinted fabrics with purple-like color were found belonged to top-class social level of the Shilla period, which informs that the purple color was used exclusively for the people of higher social status. The floss silk was found between the double woven brocade and plain woven silk of the belt, which is an important evidence that the floss silk was used for stuffing in the early 6th century.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.7-12
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• 2007

Previously study on structural design of the main wing of the twenty-seat class WIG (Wing in Ground Effect) craft. In the final design, three spars construction was selected for safety in the critical flight load, and the Carbon-Epoxy material was selected for lightness and structural stability. In this study, the forced vibration analysis was performed on the composite main wing structure of the twenty-seat class WIG craft with two-stroke pusher type reciprocating engine. The vibration analysis based on the finite element method was performed using a commercial FEM code, MSC/NASTRAN. Excitations for the frequency response analysis were assumed as the Y-mode (lateral mode), the Z-mode (vertical mode) and the $M_{xyz}$-mode (twisted mode) which are typical main vibration modes of engine. And excitations for the transient response analysis were assumed as the X-mode (longitudinal mode) with the oscillating propeller thrust which occurs in operation.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.5
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• pp.542-548
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• 2001

A robust, accurate, broad-band, alternating current sensor using fiber-optics is being developed as a part of optical over current protection relay system. The sensor uses the Faraday effect in optical fiber and polarimetric measurements tc sense electrical current. The current sensing coil consists of a length of twisted optical fiber and Faraday rotator mirror to suppress the linear birefringence effect. Due to its single-ended closed path structure, it can not only be easily installed to the target with great isolation from other fields in the vicinity, but the sensitivity can be increased by using multiple turns. This paper reports on the theoretical backgrounds of the sensor design and the preliminary experimental results.

• Journal of IKEEE
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• v.14 no.1
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• pp.33-39
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• 2010

In this paper, a 5Gb/s receiver with an adaptive equalizer for serial link interfaces is proposed. For effective gain control, a least-mean-square (LMS) algorithm was implemented with two internal signals of slicers instead of output node of an equalizing filter. The scheme does not affect on a bandwidth of the equalizing filter. It also can be implemented without passive filter and it saves chip area and power consumption since two internal signals of slicers have a similar DC magnitude. The proposed adaptive equalizer can compensate up to 25dB and operate in various environments, which are 15m shield-twisted pair (STP) cable for DisplayPort and FR-4 traces for backplane. This work is implemented in $0.18-{\mu}m$ 1-poly 4-metal CMOS technology and occupies $200{\times}300{\mu}m^2$. Measurement results show only 6mW small power consumption and 2Gbps operating range with fabricated chip. The equalizer is expected to satisfy up to 5Gbps operating range if stable varactor(RF) is supported by foundry process.

• Journal of the Korean Home Economics Association
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• v.44 no.1 s.215
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• pp.131-138
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• 2006

The yanggwan is a striped headpiece for civil and military officials worn with jebok, a costume for the royal ancestral worship ceremony, or jobok, a ceremonial costume for the courtier. It was called a jegwan when it was worn with a jebok. The geumgwan and jegwan are of the same style but the geumgwan has a gilded band and backside and the jegwan is mostly lacquered. The yanggwan was worn first with the jebok by the officials, both of which were received from the Chinese Ming dynasty in the 19th year of the King Gongmin's reign during the Goryeo period. The royal crown and court clothing system was two grades lower than the standard clothing code of the Ming dynasty of China. In the Joseon dynasty, the oyanggwan worn by the highest grade officials had five-stripes but was later replaced during the Daehan Empire by the seven-striped chilyanggwan used by Ming dynasty officials. Oyanggwans make up the majority of the surviving examples of these headpieces, with the exception of the six-striped yukyanggwan of Chung In-hak (1839-1919), the Minister of Justice, which originated in the Daehan Empire and whose owner is definitively known. The gilt portion of this yukyanggwan is finely engraved in relief with a bird, flower and tendril motif. The yukyanggwan is topped by a decorative bird ornament, called a jeongkkot. EDSS spectrum analysis of the gold plating reveals a composition of 51.32% gold and 10.34% silver. The yanggwan is composed of bamboo, mulberry paper and silk crepe. The black portions are lacquered. The individual yang is made with twisted mulberry paper.

• Journal of the Korean Society of Costume
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• v.60 no.5
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• pp.51-70
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• 2010

The ritual to change the hairstyle holds the same meaning as the coming of age ceremony. The ceremony was performed throughout three times including choga, jaega, and samga. The garment and hairstyle attuned to the ceremony formalities. Women in the royal family had 'su-siK when they were fully grown up during choga, 'gwang-sik' during Jaega, and 'keun-meo-ri (big hairstyle)' during samga. 'su-sik' is the noblest hairstyle according to social status, which is allowed to be worn only by spouse of king and prince, regardless of adult or not. During jaega, 'gwang-sik' which was 'u-yeo-meo-ri', is made by winding 'darae (wig)' around a jjok-jin-muri (bun) [Jo-jim-meo-ri]? which distinguished the hairstyle of unmarried women, who did not go through a coming of age ceremony yet. Unmarried women maintained a hairstyle which is mostly twisted into one string, but they had 'saeang-meo-ri' when they were prepared for ceremonial costumes. Also, they had 'ga-raemeo-ri' when growing further. keun-meo-ri during samga is an addition of keun-meo-ri chaebal(wig) onto u-yeo-meo-ri. Women in the royal family made geo-du-mi by adding keun-meo-ri, which is formed by twisting wig, and oimyeongbu (noble ladies) and sanggung (court ladies) added a wooden wig called u-yeo-mi. Also, yeoryeong wore ga-ri-ma. In this way, the types of hairstyles were distinguished according to hierarchy. As the coming of age ceremonial dress. Wonsam was worn. During choga. wonsam was worn as a formal dress and during jaega and samga wonsam was worn as a full dress.

• Journal of the Korean Society of Costume
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• v.60 no.5
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• pp.117-127
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• 2010

In this study, hyperspace is a result of imagination created by means of facts and fiction, represents a transfer to determination and indetermination, and means an extension to an open form. In other words, hyperspace is a high dimensional space expanded to imagination through the combination of the viewpoint on facts in this dimension and fiction. When the 2D plane surface or 3D symmetry is destroyed, or when the frame is twisted or entangled, the non-Euclidean geometry is created eventually. And when the twisting leads to transmutation and the destruction of the form reaches the extreme; this in turn became the twisting like Mbius band. Likewise, the non-Euclidean geometry is co-related to the asymmetry of the Higgs mechanism. When the 'destruction of symmetry' is considered, symmetric theory and asymmetric world can be connected. The asymmetry in turn can maintain balance by arranging the uneven weights at different distances from the shaft. Moreover, at this the concept of the upper, lower, left and right, which was included in the original form, may be crumbled down. The destruction of the symmetry is essential in order to present forecast that coincides with the phenomenon of the real world. Non-Euclidean geometry characteristic is expressed by asymmetry, twists, and deconstruction and its representative characteristic is ambiguity. The boundary between the front, back, upper, lower, inner and outer is unclear, and it is difficult and vague to pinpoint specific location. The design that does not clearly define or determine the direction of wearing costume is indeed the non-oriented design that can be worn without getting restricted by specific direction such as front and back. Non-Euclidean geometry characteristic of hyperspace have been applied to create new shapes through the modification of the substance from traditional clothing of the eastern world to modern fashion. The way of thinking in the 'hyperspace' that used to be expressed in the costumes of the east and the west in the past became the forum for unlimited creation.

• Journal of the Korean Society of Costume
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• v.58 no.5
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• pp.87-101
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• 2008

The purpose of this study is to identity the representative flower patterns in the Joseon Dynasty and investigate their chronological transitions. In the early Joseon Dynasty (i.e. 16th century), lotus patterns were very popular. Often lotus patterns were twisted around by ivy-leaves or decorated with treasures pattern in the margin. In the mid Joseon Dynasty (i.e. from 17th to mid 18th century), however, lotus patterns evolved from the typical lotus and ivy pattern and diversified into four types. In the 19th century, lotus pattern almost disappeared from the textiles of everyday dresses and were only found in the textiles of formal dresses or in special cases as in the cover pages of Buddhist scriptures. Poeny patterns was rarely used in textiles of 16th century, presumably because of the huge popularity of the lotus pattern. However, suddenly in the 17th century, Poeny patterns appeared quite frequently. There were 3 types of Poeny patterns. Poeny patterns became more popular over the years and it finally became a primary motive in textiles patterns for 100 years starting in the late 19th century. There were two types of Poeny patterns : one was realistic and true to life even in sizes, the other was more symbolic. Textile patterns combining four kinds of flowers started to appear from the late Koryo Dynasty but Flower patterns representing four seasons with distinct shapes appeared only in the 17th century. They could be categorized into three types. In the late 18th century, Flower patterns representing four seasons no longer appears in textile patterns, presumably due to a new preference for lucky omen over natural motives.

• ALGAE
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• v.32 no.3
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• pp.171-179
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• 2017

The strictly freshwater red algal order Batrachospermales has undergone numerous taxonomic rearrangements in the recent past to rectify the paraphyly of its largest genus Batrachospermum. These systematic investigations have led to the description of new genera and species as well as re-circumscription of some taxa. Specimens collected from two locations in the southeastern USA were initially identified as being allied to Batrachospermum sensu lato, but could not be assigned to any recognized species. Representative rbcL (plastid) and COI-5P (mitochondrion) sequences showed these specimens to be similar to each other and not closely matching the previously published sequence data for other Batrachospermum taxa. Comparison of sequence variation and morphology with a broader range of batrachospermalean taxa resulted in the proposal of a new monotypic genus Lympha mucosa gen. et sp. nov. to accommodate these specimens. Lympha mucosa is sister to members of a newly described genus Volatus, but the two genera are easily distinguished based on straight versus curved, twisted or spirally coiled carpogonial branch, respectively. This new taxon has morphological similarities to Batrachospermum sections Turfosa and Virescentia, but can be differentiated based on genetic divergence in rbcL and COI-5P as well as a combination of morphological characters: dense, compressed whorls, axial carposporophytes with a single type of gonimoblast filament; cortication of the main axis closely appressed; and short, straight carpogonial branch arising from the pericentral cell and carpogonia with unstalked, lanceolate trichogynes. This new taxon adds to the freshwater red algal diversity of the southeastern USA, a region already known for biodiversity and high endemism of the aquatic flora and fauna. It is also a relevant new addition to the taxonomic knowledge of the freshwater red algal Batrachospermales.