• Journal of the Korea Institute of Building Construction
• /
• v.23 no.6
• /
• pp.683-692
• /
• 2023

This research assesses the mechanical properties of concrete, utilizing both normal and lightweight aggregates, through measurements of compressive strength and ultrasonic pulse velocity. The study observed that concrete with normal aggregates exhibited higher compressive strength in its initial stages, whereas concrete with lightweight aggregates showed increased strength over time, likely attributed to the higher water absorption rate of lightweight aggregates. Ultrasonic pulse velocity generally registered higher in normal aggregate concrete, barring a specific duration, presumably due to variations in the internal pore structure of the aggregates. The correlation coefficient(R²) for the strength prediction equation, derived from the relationship between compressive strength and ultrasonic pulse velocity, exceeds 0.95. This high correlation suggests that the predictive equation based on these experimental findings is a reliable method for estimating concrete strength.

• Journal of the KSME
• /
• v.19 no.4
• /
• pp.273-278
• /
• 1979

화학적 가공이란 화학적 절식이라고 말할 수 있는 방법으로서 주조 또는 공작기계에 의한 절삭 가공대신에 약품에 의한 용해작용을 이용해서 성형품을 만드는 방법이라 할 수 있다. 이 방법은 금속자의 눈금의 조각이나 프라스틱 제품에 눈금을 넣는 금형등에 이용되고 있다. 이는 원래 항공기공업방면에서 중용되어 개발된 기계가공에 대응하는 방법이다. 크기나 정밀도에 있어서 주조(die casting)가 부적당한 경우 혹은 모양이나 능률에 있어서 기계절삭에 의하는 것이 부적 당한 경우에는 이 방법이 이용된다. 최근에 와서는 항공기기계제작 분야에 있어서의 알루미늄의 표면가공뿐만 아니라, 자동차, 건축부분의 구조부품의 성형분야에도 진출하는 경향이 있으며 가 공대상금속도 실용금속일반에 걸쳐 확대되어 감으로써 가장 용도가 넓은 철강류에 확대되어 감 으로써 가장 용도가 넓은 철강류에 까지도 응용되어 가는 실정이다. 이와 같이 종래의 기계적인 수단이 유일한 방법이라고 생각되었던 금속가공분야에 있어서 이러한 화학적 가공법이 도입되 었다는 것은 십분주목할만 한 가치가 있다. 이 화학적 가공법의 특징을 종래의 기계가공법과 비교하면 다음과 같다. (1) 피가공판의 크기는 이를 수용하는 가공조의 용량에 따라 제한될뿐이며 어떠한 대형 물이라도 가공 가능하다. (2) 가공모양은 자유롭게 설계할 수 있고 더욱이 1매 금속 판에서 1공정으로서 복잡한 모양으로 성형할 수 있다. (3) 따라서 이작업에서는 리벳팅, 용접등의 부대작업을 필요로 하지 않는다. (4) 그 가공면은 일반으로 평활하고 마루리 연마공정을 생략할 수 있다. (5) 가공조작이 간편하여 특별한 숙련을 요하지 않고 설비도 가공조의에는 별로 고가의 기기류가 필요치 않다. (6) 이상과 같은 이유에서 본법의 가공비는 기계가공에 비해서 일반적으로 저렴하다. Symposium보고및 전문서가 많이 있으나 여기에는 중요한 몇가지만 소개한다.

• Journal of the Korean Geographical Society
• /
• v.33 no.1
• /
• pp.75-91
• /
• 1998

The purpose of this paper is to investigate office location dynamic in Seoul and to analyze comparatively the office activities of emerging office centers. Since mid 1980s, the expansion of office employment and spatial differentiation of the office-type jobs have changed the employment and spatial structure of Seoul. The major employment centers are CBD, Kangnam district and Youido. Among these, CBD and Kangnam have developed as the two leading centers of Seoul. Youido, the typical office-oriented center, shares CBD functions especially specializing security business. Selective decentralization of offices made qualitative differences among the centers. In spite of vigorous office decentralization, CBD has kept the principal offices of finance and insurance, travel agencies, advertising agencies, management consulting firms, major public institutions and headquarters of upper 100 companies in Korea. But the offices of producer services such as law, architects, engineering and computer consulting and real estates and headquarters of upper 5000 companies in Korea have been decentralized dominantly to Kangnam.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.32 no.1
• /
• pp.31-43
• /
• 2014

The purposes for this research were to find the correct building background of Jondeokjeong(尊德亭) in the rear garden of Changdeok Palace(昌德宮) based on the historical facts for the area of Jondeokjeong and investigate the internal theory of construction through the metaphysical consideration. The results were as follows. 1. Building background of Jondeokjeong was related to Sohyunseja(昭顯世子) and Bongrimdaegun(鳳林大君) as forms of rear garden where was not built in the area of Jondeokjeong, bamboo pavilion, hexagonal pavilion, octagonal pavilion, etc. They were built two or three times after returning of Sohyunseja and Bongrimdaegun from China, and the area of Jondeokjeong was continuously developed by building Chunhyanggak(天香閣), Mangchunjeong(望春亭) and Cheoknoidang(滌惱堂) after Hyojong(孝宗) succeeded the royal authority of Hyunjong(顯宗) who was born in Shenyang(瀋陽) and hung a signboard of Jondeokjeong after then, etc. 2. Dazhengjeon(大政殿) of Shenyang Palace(瀋陽故宮, 1625) played the roles of major hall, Jeongjeon(正殿) which held national big events as a one-storied building with two piles of roof similar with Jondeokjeong (1644). Also, it was the building encountered when Sohyunseja and Bongrimdaegun participated in breakfasts held in the palace or banquets supervised by a king, so building background of Jondeokjeong was judged to be related with Dazhengjeon. 3. In consideration of characteristics which are shown commonly in Jondeokjeong and Dazhengjeon, relations of two buildings were verified and characteristics of Jondeokjeong were examined. First, dragon which is representatively symbolizing royal authority was formed. Therefore, Jondeokjeong was judged as a garden building which purposes were to obtain and train natural reasons, govern the nation and let people comfortable. Second, the purposes of sun dial, Ilyoungdae(日影臺) were judged to examine the accurate time and express appropriateness of the king. Third, Taechungmun(太淸門) around there is related to Samcheong(三淸) of Taoism and judged to be caused by floral wall and secular happiness accomplishment for king's longevity without disease. Fourth, for building style, one-stories pavilion of duplicated roof and building with only cylinder were to king's embodiment of supporting the sky and governing the nation.4) 4. By examining the differences between Jondeokjeong and Dazhengjeon, Jondeokjeong's own characteristics were considered. First, constructive characteristics of Jondeokjeong were changed by existing of pond and it was changed for characteristics, location and function of pavilion built in the garden while accepting oversea culture and embodied by absorbing to Joseon culture. Second, the appearance of the pond in Jondeokjeong was shown as the situation that half moon typed pond with the form of young moon is full by stream to the East. It was to express movement of moon which was always changed through the form of pond and stream of water iconographycally and it was considered as an imaginary environment method of the period.

• Archives of design research
• /
• v.20
• /
• pp.293-304
• /
• 1997

The Wiener Werkstatte created the most avangarde textile designs in Europe at the end of the 19th and the beginning of the 20th century. This study is to examine the distinctive characteristics of the textile design of the Wiener Werkstatte. The purpose of this study is to analyze the textile designs of the various designers who had contributed to shape the characteristics of the Wiener Werkstatte at various stages, and to catagorize the designs according to the subject matter, the design sources, the layout, the design principles, and the usages. The textiles of the first half of the Wiener Werkstatte are wovens for the homefurnishings. They were used as upolsteries. Wall coverings, and curtains in the commissioned buildings and houses which Hoffman designed and built in conjunction with the Wiener Werkstatte. The designs of this period have the simple and bold characteristics using less then three colors in a design. The subject matters used in the designs are firstly, stylized animals and plant forms; secondly, the purely geometric forms derived from the architural buildings. The textiles of the latter half of the Wiener Werkstatte put more emphasis on the printed textiles for the women's apparels. The textile designs of this period are categorized into four groups : firstly, the designs that stylized plant forms ; secondly, reinterpretational designs; thirdly, ethnic designs : and fourthly, the geometric art deco designs. The number of colors used in a design range up to 7 colors and all over, stripe, and ogee layouts are used.

• Korea Science and Art Forum
• /
• v.37 no.5
• /
• pp.119-133
• /
• 2019

This study is as skyscrapers are becoming increasingly taller, more constructors have decided the height alone cannot be a sufficient differentiator. As a result, atypical architecture is emerging as a new competitive factor. Also, it can be used for symbolizing the economic competitiveness of a country, city, or business through its form. Before the introduction of digital media, there was a discrepancy between the structure and form of a building and correcting this discrepancy required a separate structural medium. Since the late 1980s, however, digitally-based atypical form development began to be used experimentally, and, until the 2000s, it was used mostly for super-tall skyscrapers for offices or for industrial chimneys and communication towers. Since the 2000s, many global brand hotels and commercial and residential buildings have been built as super-tall skyscrapers, which shows the recent trend in architecture that is moving beyond the traditional limits. Complex atypical structure is formed and the formative characteristics of diagonal lines and curved surfaces, which are characteristics of atypical architecture, are created digitally. Therefore, it's goal is necessary to identify a new relationship between the structure and forms. According to the data of Council on Tall Buildings and Urban Habitat (CTBUH), 100-story and taller buildings were classified into typical, diagonal, curved, and segment types in order to define formative shapes of super-tall skyscrapers and provide a ground of the design process related to the initial formation of the concept. The purpose of this study was to identify the correlation between different forms for building atypical architectural shapes that are complex and diverse. The study results are presented as follows: Firstly, complex function follows convergence form characteristics. Secondly, fold has inside of architecture with repeat. Thirdly, as curve style which has pure twist, helix twist, and spiral twist. The findings in this study can be used as basic data for classifying and predicting trends of the future super-tall skyscrapers.

• Journal of the Korea Institute of Building Construction
• /
• v.19 no.2
• /
• pp.175-184
• /
• 2019

This paper presents a modeling prototype that optimizes construction processes implementing information communication technology (ICT). Using "IAMB", each and every actual steps of the construction process may be defined visually and explicitly by elaborating ICT to improve productivity and management efficiency. It contributes to identify the features on what parts of construction task are covered by ICT, and the effects of ICT on process performance. After analyzing 10 real project cases, ICT application types are classified into four categories according to ICT type, job functions that ICT applied, and the project phase in which ICT used. As a reuslt, it was confirmed that the positive outcomes on the construction process were beneficial to mostly the general contractors and mainly obtained by automated information processing, external consignment and consistent information use. Negative effects, which were occurred by mainly manual manipulation and duplication of information handling, were accrued to general contractors minimally, but to subcontractors maximally. Expert focus group commends that several important issues should be considered when implementing ICT.

• The Journal of the Acoustical Society of Korea
• /
• v.40 no.6
• /
• pp.593-606
• /
• 2021

The present study investigated the sounds at 13 points in the four districts in Cheongju including commercial district, historic district, urban walking district and university campus in order to realize the soundscape of the city. In order to this, questionnaire survey was conducted to 65 citizens and 5 acoustic experts on sites to find both sound loudness and annoyance of each district. At the same time, information about loud, unpleasant, preferred and representative sound of each district were acquired by selecting three from 35 sounds which consist of natural, artificial and machinery sounds. As a result, it was found that there is a very close correlation between sound loudness and annoyance. Through the analysis of sounds at each district, it was revealed that machinery sounds dominate in commercial area as figure sound, It was also shown that artificial and natural sounds dominate in historic area, artificial sounds in both urban area and university campus respectively. Laboratory listening tests were undertaken to 20 people using recorded sounds and video captured on site. The results denote that machinery and artificial sounds are regarded as most loud, machinery sounds as most unpleasant, natural and artificial sounds as most pleasant which shows similar tendency of on-site evaluation.

• The Journal of the Petrological Society of Korea
• /
• v.27 no.4
• /
• pp.195-205
• /
• 2018

Noerok is a green pigment made of mineral used the Gachil(priming coat) of wooden architecture in Chosun Dynasty era. It has been reported that various Noerok are discovered in Janggimyeon, Pohang. In this study, The Noerok from two places is compared and discussed. Noerok in the two places has blulsh-green to green color, and it is similar to their occurrences on fracture filling, vein and dike on outcrop. However, there are differences between two sites according to its petrological feature, mineral composition and geochemistry. While the Noeseongsan sample is mostly celadonite, Gwangjeongsan samples are characterized by celadonite with varying contents of cristobalite, tridymite, feldspar, along with some vitrified contents. In terms of major elements, the amount of $Al_2O_3$, $Fe_2O_3$, MgO and $K_2O$ decreases linearly with increasing $SiO_2$, whereas $Fe_2O_3$ is linearly proportional to MgO. In summary, Noerok in the study areas can be classified into 4 types (type 1, type 2, type 3-1, type 3-2) base on color, mineral composition, elemental composition, and vitrification grade.

• Korean Journal of Construction Engineering and Management
• /
• v.23 no.3
• /
• pp.13-24
• /
• 2022

Construction projects are exposed to various types of risks, which tend to increase. The increasing risks call for contractors' more attentions to forecasting and dealing with these risks. One of the measures to deal with contractors' risks is to forecast or estimate risk cost and include it in the construction budget. Although various researches in relation to risk cost have been observed, little attention has been paid to general contractors' perceptions and current practices in estimating risk cost of construction budget. The objective of the study is to identify and discuss key characteristics and implications based on the survey and analysis of general contractors' perceptions and current practices in estimating risk cost of construction budget. The study shows that there is a gap between the perception and the practice of estimating risk cost, that is, high perception of the importance of risk cost and a relatively low level of practice. It suggests that historical cost data, guidelines and corporate-level standard procedures are required to improve the current practice in addition to sufficient time allocations for risk cost estimating. It discusses that there is a need for using sophisticated estimating techniques including bid data analytics despite a low level of the current adoption, and also proposes that research and development in the field of the sophisticated estimating techniques should be further implemented in order to increase their practicality.