• Journal of Drive and Control
• /
• v.16 no.2
• /
• pp.30-35
• /
• 2019

EPPR (Electro-hydraulic Proportional Pressure Reducing) valves are pressure control valves. In this study, an independent metering valve (IMV), which is a combination of a spool valve opened and closed with the help of an EPPR valve, was discussed. The overall performance of the valve (IMV) was obtained by the respective modeling and simulation of the system. The valve investigated in this study is to be used for independent metering of hydraulic excavator actuator e.g. boom, arm, bucket etc. To design the model, continuity equations and force balance equations were used. The set of differential equations were then simulated in Simulink using ODE45 option in the configuration toolbox. The valve has to be able to control the flow rate going in and out of the cylinder separately, which is why the particular configuration was needed and selected.

• International Journal of High-Rise Buildings
• /
• v.9 no.4
• /
• pp.377-386
• /
• 2020

Beginning a few decades ago, Baku, the capital city of Azerbaijan, has experienced a dramatic construction boom that is revitalizing its skyline. The expansive growth looks to uphold the historic past of Baku as a focal point within the Caspian Sea Region while also evoking aspirations for a city of the future. With superstructure complete and interiors progressing, the Ministry of Taxation (MOT) tower is the latest addition to the city, with its stacked cubes twisting above a multi-level podium at the base. Each cube is separated by column-free green roof terraces, creating unique parametric reveals of the developing surroundings. Aside from MOT's stunning shape, its geolocation resulted in unusually high wind loads coupled with high seismic hazards for a tower of its height. In addition, limitations on possible structural systems required stepping away from a typical prescriptive code-based approach into one that utilized Performance-Based Design (PBD) methods. This paper presents the numerous structural challenges and innovations that allowed the design of a new icon to be realized.

• International Journal of High-Rise Buildings
• /
• v.12 no.3
• /
• pp.195-201
• /
• 2023

This paper reviews the history of the birth and development of the skyscraper in Japan, mainly from the perspective of the legal system, and presents the following points: 1) After 1919, building height was limited to 31 m or less, which continued after the war and defined the skyline of Japan's major cities; 2) The 31-meter height limit became a problem during rapid economic growth. With the development of tall building construction technology, the height limit was eliminated, and skyscrapers were born in Japan in the 1960s; 3) Later, the number of skyscrapers increased more rapidly in the post-bubble period after the collapse of the bubble economy in the 2000s than in the boom years of the 1980s, when the floor-area ratio was relaxed for economic uplift and urban renewal. The number of skyscrapers increased rapidly against the backdrop of the deregulation of the floor-area ratio.

• Korean Institute of Interior Design Journal
• /
• v.25 no.3
• /
• pp.121-128
• /
• 2016

Focusing on the cases applied to korean brand-name apartments In 1960s, economical growth and introduction of western-type cultures led to a boom of apartment construction. After internationalization'in 1980s through Olympic games in 1988, korean culture has attracted attention and individual life quality has been improved. Since 1990s, changes in personal life style has affected the housing culture and the construction companies started moving from quantitative supply to developing their own differential characteristics. Differentiation scheme triggered by construction companies since mid-1990s mainly focused on various ideas for space deployment. Space plans include such things as a private ground, a kitchen in the south, etc. while interior plans include to provide selection of the korean traditional style, natural or casual one. 'korean traditional style' apartment is one of such theme of the brand-named apartment. Interests on 'Tradition' can be broken down into a social trend and media trend. Firstly, the former includes the designation of Bukchon as a reserving area, one of the governmental 'Hanok Survival Program', and traditional building promotion scheme on the basis of construction policy plans. Secondly, the latter covers the interests which attract through the media showing oriental cosmetics, korean culture export via Hallyu, popularity of korean dramas, etc. Thus, it seems worth studying on the apartments with traditional factors. And also, this study aims to setup the concept and trends of korean traditional style apartments through the interior expression on the korean-factor space developed by brand-name apartments so that it could correct such false knowledge out of misunderstood concept of traditional space which results from simple decoration or structure type not accompanying Korean emotion or spirit rendered by some misleading media.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.43 no.5
• /
• pp.659-666
• /
• 2023

Characterized by boom-and-bust cycles, low entry barriers, and an almost perfectly competitive structure, the construction industry presents a unique challenge for the survival and growth of its constituent companies. A crucial aspect of this challenge is the ongoing monitoring of their financial health and business performance. To understand the typical financial and operational status of construction companies, this study analyzes the financial statements of 6,252 such companies, all of which have undergone at least one external audit between 2000 and 2019. These statements were used to develop combined financial profiles and derive industry averages. The findings indicate that the construction industry experiences limited growth in sales and profitability. High leverage ratios can jeopardize financial stability, pushing companies to seek production efficiency, such as enhancing gross asset turnover. This tendency has been particularly noticeable in the aftermath of the global financial crisis in 2008.

• Korean Journal of Construction Engineering and Management
• /
• v.17 no.3
• /
• pp.143-155
• /
• 2016

Recently, the interest on applying AVM(Around View Monitoring) systems in construction equipments have been increasing due to the demand for better control, work efficiency and safety. Most of the existing AVM systems have been developed focusing on the application in automobiles and only several AVM systems have been developed for construction equipments. However, the original technology of AVM remained the same as in the automobiles that failed to consider the main properties of construction equipments and suggest appropriate range of AVM display (Top-view). Therefore, the purpose of this study is to suggest a pilot type of AVM system for construction equipment. Accordingly, literature review, deduction of main consideration factors, selection of sensors, system design, algorithm development of a pilot type of AVM system for construction equipment have been conducted. A laboratory experiment has also been conducted for the deduction of further improvements. As a result, a minimum image refresh rate of 20 fps has been achieved that clearly reflects the actual situation of the equipment and also, the actual motions of Boom, Arm, Bucket have been displayed appropriately on the AVM system based on the angle data collected by sensors. However, the experiment results have also shown that the following tasks still remain for future work: 1)Improvement of AVM image interpolation, 2)Development of calibration module for variety construction equipment.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.12
• /
• pp.1901-1907
• /
• 2010

A hydraulic cylinder is a primary component of an excavator and is used for activating attachments such as boom, arm, and bucket. Generally, the cylinder is prone to structural problems such as buckling and fatigue failure caused by cyclic high pressure. Therefore, the safety margin for fatigue, yield, and buckling during the design lifetime should be evaluated at the durability-design stage. The durability design includes basic and detailed stages. In the basic design, the principal dimensions of the rod and tube are determined by considering the working force, speed, and range with respect to yield and buckling. In the detailed design, the dimensions of the rod notch, welds, tube end, gland, orifice, and cushion ring are determined by considering the fatigue safety. We present and discuss the overall procedure for durability design and the related analysis techniques.

• Korean Journal of Construction Engineering and Management
• /
• v.17 no.1
• /
• pp.18-27
• /
• 2016

The purpose of this study is to classify main risk factors on a construction phase of a plant project and analyze importance by the risk factors. Plant Industry is continuing boom and the increase in overseas plant orders in 2014 has showed a performance increase of 61% of the total orders, as the plant industry are risk factors for the construction phase, safety management target recognition and variety of accident prevention and safety factors by importance, etc. a situation that requires the development and introduction of management. So, it is performed that collected disaster conditions data on a construction phase of a plant project, is questioned by plant construction professional and is classified by 4M. Then, it is performed that is questioned by plant construction and safety professional in order to apply AHP method, and is presented from analyzing the risk factors, which are results of the survey, by importance and priority. This study will recognize from identifying the main risk factors in advance and will be utilized as a basic data is to prevent the risk factors.

• Journal of the Korean Society of Industry Convergence
• /
• v.9 no.1
• /
• pp.29-35
• /
• 2006

The population of Daegu, the third biggest city in Korea, is two point six million. Daegu is known as a basin or a city where it is not only too hot in summer but also too cold in winter. Recently with redevelopment apartment house boom, a 40-story or more apartment complexes are under construction near Shin-cheon and Dondaegu-ro, the south-north axis of Daegu. It is necessary to raise several points about blocking a road of the wind by high-rise apartment buildings and apartment complexes. As a kind of the green policy, Daegu enlarge the distance between apartment building by reconstructing low-rise apartment into high-rise and impose a duty of a green space on the ground by making a parking zone into an underground. Through this process, apartment complexes changed from a '一'shape to a '口'shape. It increases heat island phenomenon of a city by blocking a road of the wind that comes from Shin-cheon and Dondaegu-ro. To circulate the polluted air of Daegu basin, we need local wind. There are four effective measures. 1) Throw three greens into one in the center of the road at the north side in the same way of the south side of Dongdaegu-ro, 2) reflect the information of roads of the wind including heights, spaces and directions of buildings, 3) steer clear of a high-rise buildings and development apartment house constructions, and 4)select a city for benchmarking to be the environmental capital.

• Journal of Drive and Control
• /
• v.10 no.1
• /
• pp.29-36
• /
• 2013

Excavation is an important work in mining, earth removal and general earthworks. Nowadays, automation in excavator has been studied by several researchers. In the excavator research methods, simulation is one of the low cost methods for applied to test safely. In this paper, designed a virtual hydraulic excavator that with the control and the dynamic. At first, the simulation of hydraulic system for excavator's attachment such as boom, arm and bucket using Matlab/Simhydraulic is presented. Second, the dynamic model of excavator is distributed to combine with the hydraulic system. For controlling this system, electric joysticks are used to operate the orifice open areas in Main Control Valve. The simulation result is described to analysis the performance of this virtual excavator.