• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.3
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• pp.281-301
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• 2024

The power cable tunnels which are part of the underground transmission line project, are constructed using the shield TBM method. The disc cutter among the shield TBM components plays an important role in breaking rock mass. Efficient tunnel construction is possible only when appropriate replacement occurs as the wear limit is reached or damage such as uneven wear occurs. A study was conducted to determine the wear conditions of disc cutter using a deep learning algorithm based on real-time measurement data of wear and rotation speed. Based on the results of full-scaled tunnelling tests, it was confirmed that measurement data was obtained differently depending on the wear conditions of disc cutter. Using real-time measurement data, an algorithm was developed to determine disc cutter wear characteristics based on a convolutional neural network model. Distributional patterns of data can be learned through CNN filters, and the performance of the model that can classify uniform wear and uneven wear through these pattern features.

• Journal of Korean Society of Forest Science
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• v.89 no.4
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• pp.502-512
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• 2000

Old-growth development for two different second-growth northern hardwood stands in the North America was evaluated with a computer simulation. The two sites compared were a representative 77 year old even-aged stand (Phelps) with heavy dominance by pole size classes, and an older uneven-aged stand with some existing old-growth structural features (Wildcat Creek). Each stand was evaluated in its natural progress toward old-growth structural conditions with stand structure, size distribution of live and dead trees, percent stand area in canopy gaps, and visual canopy profile and overhead view. The Phelps stand reached the minimum structural threshold for the old-growth stage after 74 years. Only 13 years was required for Wildcat Creek stand to reach the old-growth threshold. During the 45 years of simulation, the diameter distributions of both stands became broader and flatter. DBH distribution of dead trees had a general descending trend over the simulation in each stand. Gaps at Phelps were typically small after 45 years. Gap area at Wildcat Creek was somewhat more constant over the 45 years of simulation but a big gap was formed because of the death of several adjacent large trees.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.1 s.190
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• pp.27-36
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• 2007

This paper describes the development of 6-axis ankle force/moment sensor for the intelligent feet of a humanoid robot. When the robot walks on uneven terrain, the feet should perceive the applied forces Fx, Fy, Fz and moments Mx, My, Mz from the attached 6-axis force/moment sensor on their ankles. Papers have already been published have some disadvantages in the size of the sensor, the rated output and so on. The rated output of each component sensor (6-axis ankle force/moment sensor) is very important to design the 6-axis force/moment sensor for precision measurement. Therefore, each sensor should be designed to get the similar rated output under each rated load. Also, the size of the sensor is very important for mounting to robot's feet. Therefore, the diameter should be below 100 mm and the height should be below 40mm. In this paper, first, the structure of a 6-axis ankle force/moment sensor was modeled for a humanoid robot's feet newly, Second, the equations to predict the strains on the sensing elements was derived, third, the size of the sensing elements was designed by using the equations, then, the sensor was fabricated by attaching straingages on the sensing elements, finally, the characteristic test of the developed sensor was carried out. The rated outputs from the derived equations agree well with the results from the experiments. The interference error of the sensor is less than 2.94%.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1097-1102
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• 2007

This paper describes the development of 6-axis force/moment sensor for an intelligent robot's foot. In order to walk on uneven terrain safely, the foot should perceive the applied forces Fx, Fy, Fz and moments Mx, My, Mz to itself. The applied forces and moments should be measured from a 6-axis force/moment sensor attached to a humanoid robot's foot(ankle). They in the published paper already have some disadvantage in the size of the sensor, the rated output and so on. The rated output of each component sensor (6-axis force/moment sensor) is very important to design the 6-axis force/moment sensor for precision measurement. Therefore, each sensor should be designed to be gotten similar the rated output under each rated load. So, the sensing elements of the 6-axis force/moment sensor should get lots of design variables. Also, the size of 6- axis force/moment sensor is very important for mounting to robot's foot. In this paper, a 6-axis force/moment sensor for perceiving forces and moments in a humanoid robot's foot was developed using many PPBs (parallel plate-beams). The structure of the sensor was newly modeled, and the sensing elements (plate-beams) of the sensor were designed using FEM (Finite Element Method) analysis. Then, the 6-axis force/moment sensor was fabricated by attaching strain-gages on the sensing elements, and the characteristic test of the developed sensor was carried out. The rated outputs from FEM analysis agree well with that from the characteristic test.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.7 s.196
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• pp.90-97
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• 2007

This paper describes the development of 6-axis force/moment sensor considered adult weight far an intelligent foot of humanoid robot. In order to walk on uneven terrain safely, the foot should perceive the applied forces Fx, Fy, Fz and moments Mx, My, Mz to itself and control the foot using the forces and moments. The applied forces and moments should be measured from a 6-axis force/moment sensor attached to the foot, which is composed of Fx sensor, Fy sensor, Fz sensor, Mx sensor, My sensor and Mz sensor in a body. Each sensor should get the deferent rated load, because the applied forces and moments to foot in walking are deferent. Therefore, one of the important things in the sensor is to design each sensor with the deferent rated load and the same rated output. In this paper, a 6-axis force/moment sensor (rated load of Fx and Fy are 500Nm and Fz sensor is 1000N, and those of Mx and My are 18Nm, Mz sensor is 8Nm) for perceiving forces and moments in a humanoid robot's foot was developed using many PPBs (parallel plate-beams). The structure of the sensor was newly modeled, and the sensing elements (plate-beams) of the sensor were designed using by ANSYS software (FEM (Finite Element Method) program). Then, a 6-axis force/moment sensor was fabricated by attaching strain-gages on the sensing elements, and the characteristic test of the developed sensor was carried out. The rated outputs from FEM analysis agree well with that from the characteristic test.

• New & Renewable Energy
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• v.17 no.2
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• pp.50-58
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• 2021

We proposed an MEA development methodology that accurately measures intrinsic MEA performance while considering the uneven reaction environments formed inside a large-area BP. To facilitate measurement of the inherent MEA performance, we miniaturized the active area of the MEA to 3 cm², and prepared two MEAs with different ionomer contents of 0.65 and 0.80 (I/C). By simulating the operating conditions of a 100 cm² BP at the inlet (I), center (C), and outlet (O), the oxygen concentration and relative humidity were determined to be 20.7, 13.8, 11.7%, and 50, 66.1, and 70.1% respectively. We measured the performance and electrochemical analysis of the prepared MEAs under the three simulated conditions. Based on the results of statistical analysis of the evaluated MEA performance data, I/C 0.65 MEA had a higher average performance and lower performance deviation than I/C 0.80 MEA. Hence, it can be concluded that an I/C 0.65 MEA is a more effective MEA for large-area BP. Based on the above research process, we confirmed the effectiveness of the proposed MEA development methodology.

• Steel and Composite Structures
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• v.41 no.5
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• pp.663-679
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• 2021

To elucidate the differences in the collapse behavior between a single-story beam-column assembly and multi-story frame, two 1/3-scale two-bay composite frames, including a single-story composite beam-column assembly and a three-story composite sub-frame, were designed and quasi-statically tested. The load-displacement responses, failure modes, and internal force development of the two frames were analyzed and compared in detail. Furthermore, the resistance mechanisms of the two specimens were explored, and the respective contributions of different load-resisting mechanisms to the total resistances were quantitatively separated to gain deeper insights. The experimental tests indicated that Vierendeel action was present in the two-dimensional multi-story frames, which led to an uneven internal force distribution among the three stories. The collapse resistance of TSDWA-3S in the flexural stage was not significantly increased by the structural redundancy provided by the additional story, as compared to that of TSDWA-1S. Although the development of the load response was similar in the two specimens at flexural stage, the collapse mechanisms of the multi-story composite frame were much more complicated than those of the single-story beam-column assembly, and the combined action between stories was critical in determining the internal force redistribution and rebalancing of the remaining structure.

• Health Policy and Management
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• v.28 no.3
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• pp.240-250
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• 2018

By the end of 2017, in a world of 7.6 billion people, there were inequalities in healthcare indices both within and between nations, and this gap continues to increase. Therefore, this study aims to understand the current status of regional inequalities in healthcare indices and to find an action plan to tackle regional health inequality through a geo-economic review in Korea. Since 2008, there was great inequality in life expectancy and healthy life expectancy by region in not only metropolitan cities but also districts in Korea. While the community health statistics from 2008-2017 show a continuous increase of inequality during the last 10 years in most healthcare indices related to noncommunicable diseases (except for some, like smoking), the inequality has doubled in 254 districts. Furthermore, health inequality intensified as the gap between urban (metropolitan cities) and rural regions (counties) for rates of obesity (self-reported), sufficient walking practices, and healthy lifestyle practices increased from twofold to fivefold. However, regionalism and uneven development are natural consequences of the spatial perspective caused by state-lead developmentalism as Korea has fixed the accumulation strategy as its model for growth with the background of export-led industrialization in the 1960s and heavy and chemical industrialization in the 1970s, although the Constitution of the Republic of Korea recognizes the legal value of balanced development within the regions by specifying "the balanced development of the state" or "ensuring the balanced development of all regions." In addition, the danger of a 30% decline or extinction of local government nationwide is expected by 2040 as we face not only a decline in general and ageing populations but also the era of the demographic cliff. Thus, the government should continuously operate the "Special Committee on Regional Balanced Development" with a government-wide effort until 2030 to prevent disparities in the health conditions of local residents, which is the responsibility of the nation in terms of strengthening governance. To address the regional inequalities of rural and urban regions, it is necessary to re-adjust the basic subsidy and cost-sharing rates with local governments of current national subsidies based mainly on population scale, financial independence of local government, or distribution of healthcare resources and healthcare indices (showing high inequalities) overall.

• Journal of the Korean association of regional geographers
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• v.10 no.2
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• pp.428-446
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• 2004

This paper is to analyze citizens' consciousness on urban changes during the 1900s in the sectors of economy, politics and socio-culture of large cities in Korea, especially comparing them in Seoul, Daejeon, Daegu, and Kywangju. The items of questionnaire are drawn from theories on each sector of new urbanization of large city in Western countries, that is, that of post-Fordism, of urban governance, of post-modernism, and of sustainable city. Some major findings of this questionnaire analysis are as follows. First, on the change of large cities in general, citizens think that the sectors of spatial structure, and of socio-culture of the cities were changed more than those of urban economy and of urban politics. Secondly, in the sector of urban economy, citizens recognize that the obstructing factors of development, that is, the lack of regional capital and the absence of head-quarter of large firms, which seems to be resulted from uneven regional development in the previous periods were much more serious than others, while acknowledging the importance of high-tech industry. Thirdly, in the sector of urban politics, citizens think that the centralized structure of politics and of political parties was still problematic, while acknowledging the importance of entrepreneur mind of urban governor. Finally, in the sector of urban socio-culture, citizens emphasize the development of telecommunication, the popularization of private automobile and the increasing use of credit card, as three major factors which have exercised major impacts on the development of urban socio-culture.

• Journal of the Korean Geographical Society
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• v.50 no.1
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• pp.73-90
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• 2015

This article focuses on geo-institutional differentiation and a multi-scalar analysis of emerging capitalist development in Laos. It discusses the impact of the Greater Mekong Subregion on new institutional economic and economic geographical arrangements. It demonstrates the usefulness of the varieties of Asian capitalism approach. The rubber industry was chosen to unravel emerging but various sub-national institutional arrangements linked to higher scale levels. Rubber is a growing agribusiness industry throughout the country, led by the insatiable demand from China. Overall, this study shows that the capitalist development of the rubber industry features much geo-institutional differentiation, due to the different strategies of Chinese, Thai and Vietnamese investors. Since Laos is still in transition from a state-led economy to something else, it is impossible at this to identify the exact number capitalisms. Yet, the evidence on rubber clearly lays bare the presence of multiple institutional arrangements. Without more inclusiveness, however, the implications for regional development are worrying. Exclusive arrangements will most likely lead to more uneven regional development and higher regional inequality. To refine theories on sub-national varieties of capitalism in developing countries it is instructive to consider more explicitly the notion of regional personal capitalisms and the complex interplay between national and regional states and relationships between capital accumulation and livelihood analyses.