• Journal of Korean Society on Water Environment
• /
• v.35 no.4
• /
• pp.332-339
• /
• 2019

A comparative study on the anaerobic digestion efficiency according to the temperature change was conducted considering the characteristics of domestic food wastes with high water content of about 80 % or more. The substrate was tested for anaerobic digestion efficiency in two substrates, a liquid component separated naturally from food waste and food waste itself. In the anaerobic digestion experiments, the digestion efficiency was the highest at $55^{\circ}C$ (thermophilic temperature). However, the digestion efficiency at $45^{\circ}C$(middle high temperature) was lower than that at $35^{\circ}C$(mesophilic temperature). The comparison of general food wastes anaerobic digestion requiring 30 days of hydraulic retention time to the liquid component indicated a stable digestion efficiency even after 15 days of hydraulic retention time.In the experiments conducted on food waste, the digestion efficiency at $55^{\circ}C$ was higher than that at $35^{\circ}C$. When the food waste, especially the liquid component originating from food waste, is treated by anaerobic digestion method, the mesophilic temperature and thermophilic temperature conditions are more favorable in the digestion efficiency than the middle high temperature ($45^{\circ}C$). However, when applying thermophilic or mesophilic temperature anaerobic digestion process operation in the field, the amount of energy input should be considered.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.09a
• /
• pp.813-824
• /
• 2010

Thermal conductivity of soils is one of the most important parameters to design horizontal ground heat exchangers. It is well known that the thermal conductivity of soil is strongly influenced by its density and water content because of soil's particulate structure. This paper reviewed and evaluated some of the commonly used prediction models for thermal conductivity of soils with the experimental data available in the literature. Semi-theoretical models for two-component materials were found inappropriate to estimate the thermal conductivity of dry state sands. It came out that the model developed by Cote and Konrad gave the best overall prediction for unsaturated sands available in the literature. Also, a parametric analysis is conducted to investigate the effect of thermal conductivity and water content, soil type on the horizontal ground heat exchanger design. The analysis shows that a required pipe length for the horizontal ground heat exchanger is reduced with the increase of soil thermal conductivity and water content. The calculation results also show that the dimension of the horizontal ground heat exchanger can be reduced to a certain extent by using backfilling material with a higher thermal conductivity of solid particles.

• Journal of Construction Engineering and Project Management
• /
• v.3 no.4
• /
• pp.12-19
• /
• 2013

Green Frame is an environmentally friendly column-beam system composed of composite PC members that can increase buildings' life spans while reducing resource consumption. Typically, connections of PC and RC columns occur at the boundaries of each floor, which is at the upper section of slabs, causing the boundary of each floor to generate the maximum moment. Although it is not optimal in terms of structural safety to connect members at a location where the moment is high, this approach is highly adopted due to its constructability. We propose that a superior approach that employs the concept of connecting columns at the low bending moment zone can be applied to quickly and safely install green columns, the main structural members of Green Frame. Connection of green columns at the low bending moment zone can be classified into three techniques, depending on the method of reinforcing the joints, which have different connection characteristics and construction methods. Research is needed to compare the features of each method of reinforcing the joints so that the most appropriate column connection method can be chosen for the site conditions. This study aims to confirm the structural safety of the connection component at the low bending moment zone and to compare and analyze the construction duration, unit price, quality and safety performance of each column connection method. The study results are anticipated to activate the use of composite precast concrete and to be used as development data in the future.

• Journal of KIISE:Software and Applications
• /
• v.37 no.7
• /
• pp.568-572
• /
• 2010

Self-healing is one of the techniques that assure dependability of mission-critical system. Self-healing consists of fault detection and fault recovery and fault detection is important first step that enables fault recovery but it causes overhead. We can detect fault based on model, the detection tasks that notify system's behavior and compare normal behavior model and system's behavior are heavy jobs. In this paper, we propose architecture-based multi-level self-adaptive monitoring method that complements model-based fault detection. The priority of fault detection per component is different in the software architecture. Because the seriousness and the frequency of fault per component are different. If the monitor is adapted to intensive to the component that has high priority of monitoring and loose to the component that has low priority of monitoring, the overhead can be decreased and the efficiency can be maintained. Because the environmental changes of software and the architectural changes bring the changes at the priority of fault detection, the monitor learns the changes of fault frequency and that is adapted to intensive to the component that has high priority of fault detection.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.4 no.4
• /
• pp.396-403
• /
• 2016

This study is based on the evaluation of a single component injection type adhesive repair material and a new 2 component type used in leakage of underground concrete structures. The studies showed that based on different mix ratio of the 2 component type adhesive sealant comprised of an asphalt main and latex mixture agent the viscosity of the material compound differed significantly. Based on a permeability testing, injection and economic efficiency, and performance, the appropriate ratio was determined to be 6:1 and was proceeded to the KS F 4935 evaluation method. The 2 component type adhesive sealant uses a static mixer and a cartridge type container for the injection procedure and was able to satisfy the evaluation criteria outlined in the KS F 4935 standard.

• Proceeding of Spring/Autumn Annual Conference of KHA
• /
• 2009.04a
• /
• pp.230-235
• /
• 2009

In our country, the application of the design method of face to face dimension in wall-slab apartment has passed 10 years. So MC design method has fixed in the design step to some degree. In Design and Work Execution of House the exclusive area of the apartment was calculated by face to face dimension. And the term of face to face dimension was known broadly to clients, construction company, etc. But design method of face to face dimension is not to simply extend the room size so far as wall depth in design process but to ensure the actual space should be considered with efficient use and assembly of building components. That is to say, Design method of face to face dimension is not to be defined by design step but to be related with construction and maintenance. However in construction process the point of face to face design method was not understood even now. So the purpose of this study was to extract the effect and question of face to face design method in construction process by survey of actual condition of structure and construction quality, and compare this result with existing construction method. The following project of this study is to survey of actual condition of interior components such as gypsum board, windows & doors etc. Therefore this study is to induce architectural long-life through architectural standardization construction and component's exchange, and, by the subject of the study on Apartment to have design guideline and basis for joining part between Gypsumboard and windows.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.24 no.6
• /
• pp.267-275
• /
• 2020

In the event of an earthquake, non-structural components require seismic performance to ensure evacuation routes and to protect lives from falling non-structural components. Accordingly, the seismic design code proposes horizontal force for the design and evaluation of non-structural components. Ground motion observed on each floor is affected by a building's eigen vibration mode. Therefore, the earthquake damage of non-structural components is determined by the characteristics of the non-structural component system and the vibration characteristics of the building. Floor response spectra in the seismic design code are estimated through time history analysis using seismic waves. However, it is difficult to use floor response spectra as a design criterion because of user-specific uncertainties of time history analysis. In addition, considering the response characteristics of high-rise buildings to long-period ground motions, the safety factor of the proposed horizontal force may be low. Therefore, this study carried out the horizontal force review proposed in the seismic design code through dynamic analysis and evaluated the floor response of seismic waves considering buildings and predominant periods of seismic waves.

• Architectural research
• /
• v.18 no.4
• /
• pp.179-184
• /
• 2016

The structure must be periodically checked and measures must be taken to prevent deterioration in building construction. From this point of view, a nondestructive test is essential to estimate whether the construction of buildings is proper, and whether the dimension of depositing concrete is consistent and without damage. This study estimated the thickness of the concrete component of construction framework using the ultrasonic velocity method and the impact echo method, in order to investigate reliability of the estimation of the thickness of normal strength concrete and high strength concrete, leading to the following conclusions. In the estimation of the thickness of the concrete structures, specimens of normal strength of 24MPa and specimens of high strength of 40MPa demonstrated an average error rate of 5.1% and 2.2%, respectively. The impact-echo method, one of the non-destructive tests, is verified as an efficient diagnostic technique. With this information, we will determine specific standards for the maintenance of structures, and the re-creation of lost building blueprints.

• Journal of the Korean Institute of Rural Architecture
• /
• v.22 no.3
• /
• pp.33-40
• /
• 2020

Wood is one of the main materials of wooden building. Hanok also uses wood as its main component. Recently, Hanok continues to be built. Wood is affected by the climatic environment. The growth of decay bacteria is activated at more than 80% relative humidity. The microclimate environment and moisture content were measured for architectural cultural properties that have been maintained for a long time as a wooden building. The method analyzed the measured data by distinguishing between cloudy and sunny days. In the case of the old house, Anchae moisture content was higher than that of Sarangchae. This seems to be due to the narrow front yard or the planting of trees. The microclimate environment inside the house began to decrease in humidity from 8 am. According to the survey data, the relative humidity was less than 80% from 9 am when there was wind around 4-6 am. It appeared an hour earlier than in the absence of wind. As a result, the time interval for dehumidifying of wood was widened. Therefore, the wooden building is open to the front so there is airflow under the eaves during the daytime and wind in the morning appear to be alternatives in order to lower the moisture content.

• KIEAE Journal
• /
• v.9 no.2
• /
• pp.73-80
• /
• 2009

In the early twentieth century, many architects still practised eclectic design elements. Emergence of new building materials such as steel, concrete and glass were not yet found fresh roles in architectural design. It was Brussels that the use of modern materials gave rise to their new forms and gave influence to not only building skins but also spatial organization. Art Nouveau architecture is often seen as revolutionary and pioneering modern architecture against eclectic classicism prevalent in the 18th and 19th centuries. Despite the fact that some scholars point out that Art Nouveau is more a transient phenomenon than modern architecture proper, no one would deny that Art Nouveau carries a good deal of modern characteristics. This paper intends to show rather ambivalent perspectives upon Art Nouveau architecture. Although it insinuates overly dynamic nature in architectural languages, it does not hamper us from reading Art Nouveau as a vital component of modern architecture. Through a careful analysis of the early domestic designs of Victor Horta, it becomes evident that his work can provide modern architecture a meaningful alibi for its growth. Victor Horta's house design is well known to the public, both for his classical tastes and for its changing implementation. Horta's modern quality is never adequately recognized, partly due to his eye catching modern iron properties and sinuous ornamentation. This paper tries to offer an insight into the complicated stage set of the fin-de-$si{\grave{e}}cle$ through the work of Victor Horta whose influence has been immense in the making of modern architecture.