• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.4
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• pp.145-152
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• 2016

For a general office building having a center core, the distinction between the outer wall and the compartment should be clear, and it should be set at a stack effect pressure distribution acting on the respective compartment by a relative area ratio of the respective leak compartment. In the case of office buildings with an independent core for core there, some blocks of shares and exterior pressure distribution in buildings and office buildings typically have different characteristics. Therefore, if the stack effect reduction measures, designed on the basis of a general office building are applied to a stand-alone building, the core of the building should reflect the unique pressure distribution characteristics. This study, performed as part of the object corresponding to the flat plan of the building in the diversification trend, analyzed the stack effect that actually occurs in an office building having the properties intended for stand-core construction, and thus on the basis of and tested by the method of using a conventional stack effect reduction measures. Reviewed in the study, an independent cored office building that does not have the air flow path through the specific space with respect to the center core type office building has a feature, and the variation in characteristics of the pressure distribution inside the building according to this air flow path stack effect was reduced by a variety of measures that should be applied to determine the application.

• Journal of The Korean Digital Architecture Interior Association
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• v.10 no.3
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• pp.5-10
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• 2010

This study aims to find out the present conditions of pilotis space, and the usage and requests of it by residents as to suggest the direction in planning pilotis spaces in apartment housing. This study selected six apartment complexes, and conducted case-studies and surveys of them. The study findings are as follows. 1) The types of pilotis spaces of the apartment housing can be categorized into an entry type, a community type, a recreational type, a bicycle storage type, a pedestrian passage type, a parking type, and a visual passage type. As a result of studying the present conditions, pilotis spaces of a recreational type were the most, and a community type and a parking type were not found. It was found that diverse types of pilotis spaces need to be planned in consideration of the characteristics of an apartment complex and its residents. 2) As for residents' time spent in using the pilotis space, they spent little time. This can be attributed to the fact that most pilotis spaces were designed only with simple flat benches, and gazebos, which seemingly failed to draw residents' attention. Therefore, the spaces need to be planned for diverse purposes after examining residents' needs, which can include indoor exercise equipments and children's play facilities. 3) Regarding the residents' requests about pilotis spaces in the apartment housing, the most widely requested was using it as a community space. Also, many requested to use it as a library, and a children's play space. Therefore, it needs to be considered to plan the pilotis space for providing diverse programs.

• The KIPS Transactions:PartC
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• v.11C no.7 s.96
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• pp.905-916
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• 2004

Self-organizing hierarchical ad hoc network (SOHAN) is a new ad-hoc network architecture designed to improve the scalability properties of conventional 'flat' ad hoc networks. This network architecture consists of three tiers of ad-hoc nodes, i.e.. access points, forwarding nodes and mobile nodes. This paper presents a topology discovery and routing protocol for the self-organization of SOHAN. We propose a cross-layer path metric based on link quality and MAC delay which plays a key role in producing an optimal cluster-based hierarchical topology with high throughput capacity. The topology discovery protocol provides the basis for routing which takes place in layer 2.5 using MAC addresses. The routing protocol is based on AODV with appropriate modifications to take advantage of the hierarchical topology and interact with the discovery protocol. Simulation results are presented which show the improved performance as well as scalability properties of SOHAN in terms of through-put capacity, end-to-end delay, packet delivery ratio and control overhead.

• Journal of the Institute of Convergence Signal Processing
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• v.20 no.4
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• pp.199-204
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• 2019

In the boundary layer, vortical system has been analyzed by the statistical methods to identify the vortex interaction. However, there are the limitations in explaining vortices by the mean velocity or the standard deviation. This paper proposed a method to establish a frequency analysis by Fourier transform in order to simultaneously investigate various scale vortices. For this purpose, the flow visualization conducted to reveal a standing vortex, a hairpin vortex and a wake region around a hemisphere attached on a flat plate in a water channel. In addition, the velocity where the hairpin vortex was being generated in the wake region was measured by a hot-film anemometer. To observe changes in the vortex interaction, suction was applied through a hole in front of the hemisphere. For the evaluation of the proposed frequency analysis, the existing statistical results were compared to the frequency analysis that corresponds to the qualitative results of the flow visualization.

• Smart Structures and Systems
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• v.22 no.4
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• pp.481-493
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• 2018

Ultrasonic guided waves have attracted increasing attention for non-destructive testing (NDT) and structural health monitoring (SHM) of bridge cables. They offer advantages like single measurement, wide coverage of acoustical field, and long-range propagation capability. To design defect detection systems, it is essential to understand how guided waves propagate in cables and how to select the optimal excitation frequency and mode. However, certain cable characteristics such as multiple wires, anchorage, and polyethylene (PE) sheath increase the complexity in analyzing the guided wave propagation. In this study, guided wave modes for multi-wire bridge cables are identified by using a semi-analytical finite element (SAFE) technique to obtain relevant dispersion curves. Numerical results indicated that the number of guided wave modes increases, the length of the flat region with a low frequency of L(0,1) mode becomes shorter, and the cutoff frequency for high order longitudinal wave modes becomes lower, as the number of steel wires in a cable increases. These findings were used in design of transducers for defect detection and selection of the optimal wave mode and frequency for subsequent experiments. A magnetostrictive transducer system was used to excite and detect the guided waves. The applicability of the proposed approach for detecting and locating wire breakages was demonstrated for a cable with 37 wires. The present ultrasonic guided wave method has been found to be very responsive to the number of brokenwires and is thus capable of detecting defects with varying sizes.

• Journal of the Korean Institute of Rural Architecture
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• v.18 no.3
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• pp.17-24
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• 2016

The aim of this study is to build an architectural landscaping design ways of vulnerable community in rural area. I surveyed scenery structures, public buildings and single home forms, and fence types of house in twelve villages which have undertaken improving environment of rural community in four provinces. They all have an inferior surroundings to live in rural village, because they were isolated from the city, located on the mountain or island, and made a living under the slate materials of roof. The central government has been driving to reform the conditions with local office, so that they may increase their living qualities and village environment to get to the general level of rural area. There are three results of this study as follows: First, the scenery of the village surveyed has a remarkable views of locality and hierarchy of layers between field and mountain, which is very identified as a typical image of Korean rural topology. Second, the public buildings and single homes and outside wall of houses were personally designed or reformed as a various types like a flat slab style and different architectural structure, because they followed only to keep the architectural code rather than to make a harmony with other traditional style buildings. When they have to remodel it again through SaethulMaul project, they are needed to consider of both architectural code and design guideline for the local landscape design image. Third, to make a different landscape view of each village and improve housing conditions, it should be taken a people participation design way.

• Journal of the Korean Institute of Landscape Architecture
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• v.23 no.2
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• pp.124-136
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• 1995

This study was conducted to find the distinguished pattern of Korean 'Dae'. Therefore, the purpose of this study is to define how the pattern of 'Dae' has been developed and what is the characteristics of the pattern of Korean 'Dae'. The summarized results are as follows; 1. The types of 'Dae'(rock in the nature, a 'Dae' built artificially, a structure) were identified in the era of the three kingdoms. And in the era of the three kingdoms, 'Dae' was regarded as: a mysterious place related with a king, the place where concrete activities of a specific person had occurred in there, and a mountain peak 2. in the era of Koryo , artificial aspect of 'Dae' were emphasized. In addition, the activities occurred in the 'Dae' took concrete shape by kings. 3. The characteristics of the pattern of 'Dae' during Chosen Dynasty are: 1) A type of huge flat rock(27.6%), a type of mounts고 peak and a type of cuff(24.1%), a type of fantastic rock(15.5%), a type of stratified rock(6.9%) were shown 2) The main activities on 'Dae' were play , observation, and rest 3) In the viewpoint of the locational characteristics, 'Dae' were found in the mountains, at the top of the mountain peaks, on high hill, on cliffs, at the riversides, and on the beaches, etc. 4. With consideration on change trend of the number of'Dae' according to literature(time) , the biggest geographical distributions of 'Dae' were shows in Hamkyungdo in noddle of 15th century (Saejongsillockjiriji), in Kangwondo in the middle of 16th century (Sinjeongdonggukyecjiseongram), in Chunrado in middle of 17th century(Donggukyeojiji), and in Kyungsangdo in middle of 18th 19th century(Yeojidoseo, Eubji) 5. Through the whole period of Chosen Dynasty, the geographical distribution of 'Dae' had much in Kyungsangdo and Pyungahndo.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.2
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• pp.180-187
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• 2018

Corrugated bulkhead has been adopted for cargo tank bulkheads of commercial vessels such as bulk carriers, product oil carriers and chemical tankers. It is considered that corrugated bulkhead is a preferred structural solution, compared to the flat stiffened bulkhead, due to several advantages such as lower mass, easier maintenance and smaller corrosion problems. Many researches to find the optimum shape of corrugated bulkhead have been mostly carried out for bulk carriers. Compared to corrugated bulkheads of bulk carriers, ones of chemical tankers are more complicated since they are composed of transverse and longitudinal bulkheads, and they are made of higher priced materials. The purpose of this study is the development of minimum weight design method for corrugated bulkhead of chemical tankers. Evolution strategy is applied as an optimization technique. It has been verified from many researches that evolution strategy searches global optimum point prominently by using multi-individual searching technique. Multi-individual searching methods need excessive time if they connect to 3-D finite element model for repetitive structural analyses. In order to resolve this issue, 2-D beam element connected to deck and lower stool is substituted for a corrugated structure in this study. To verify the reliability of the structural responses by idealized 2-D beam model, they have been compared with ones by 3-D finite element model. In this study, optimum design for corrugated bulkhead of 30 K chemical tanker has been carried out, and the results by developed optimum design program have been compared with design data of existing ship. It is found out that optimum design is about 9% lighter than one of existing ship.

• Journal of the Korean Institute of Rural Architecture
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• v.23 no.4
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• pp.13-20
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• 2021

This study aims to provide necessary, basic data for future space planning of rural housing through a survey on the size of residential space and space utilization of rural housing. To this end, this study analyzed the size and space of rural houses in actual use, and also analyzed the size and characteristics of the essential space for life, which were collected via a survey. In particular, Usan Village in Jangheung, where various types of houses and renewed houses coexist due to continued changes in the form of traditional villages, was selected for a target site of this study. In next step, this study analyzed the current status of use of each house in the village and compared the size of each space and the characteristics of space utilization. The results of the survey on Usan village, on where divergent traditional and modern houses are located, are as follows. First, Usan Village has total 31 traditional and modern houses. Most of the houses have been aging and formed into old-age households, and the expansion, renovation, and construction of farmhouses have progressed. Second, the population of Usan Village has decreased, and the number of residents per household is currently 1.4. Third, the survey indicates that the flat area of rural houses was 80.6m², the average area of living space was 54.1m², and the average area of water storage space was 26.5m², and the main living area was changed to water storage space due to the decrease in the number of household members in rural areas.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.32 no.1
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• pp.74-82
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• 2014

The purposes of this study is to investigate spatial structure characteristics of earthen walled fortresses based on topography, which are locational and Plane morphology, Cross sections of earthworks. Target areas of this study are 37 earthen walled fortresses which are designated as cultural properties. This study is conducted with methodologies of literature review, field investigation, investigation on topography materials and relation analyses of topography&spatial structure. The results from study on spatial structure of earthen walled fortresses are as follows. First, Earthen walled fortresses on flat topography were adjacent to water systems like rivers or streams. Plane morphology showed regular shapes. The cross section morphology presented trapezoid the most with earthworks of which outer and inner walls were built. Second, More than 70% of earthen walled fortresses on hilly topography had water system within close range of approximately 1.5km. Plane morphology was mainly with more than 73% of irregular types. Cross sections of earthworks were of morphology with more than 86% of bordered type and another type leaning against existing topography like mountains. Third, 59% of earthen walled fortresses in mountain areas had water system within their close range, which indicated that they depended on external water system less than those with hilly topography. Plane morphology was mainly with more than 67% of irregular types. Cross sections of earthworks were of monoslope method with more than 94% of bordered type and another type leaning against mountains.