• Korean Journal of Construction Engineering and Management
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• v.19 no.1
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• pp.65-73
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• 2018

Since unfair trading practices between participants in construction project are common, the government has enforced several policies and systems to prevent or minimize the unfair trading practices in construction industry. However, not much attention has been paid to figure out which policies or acts are working or not. This paper analyzed the effectiveness of the policies and acts which are being implemented to prevent unfair trading practices and provided several suggestions to improve the performance of those acts. Survey was conducted to industry experts to collect data regarding their perceptions on those policies and acts. Then the effectiveness of the policies and acts were analyzed in terms of their importance and performance through IPA (Importance-Performance Analysis) based on the survey result. It was found through IPA that execution related acts such as investigation, exposure, and punishment for unfair trading practice have shown low effectiveness in entire construction process and dispute arbitration and mediation related center operated by authority showed low performance too. To improve the effectiveness of those acts, dispute arbitration system improvement, investigation & reporting system consolidation and enhancement practical binding force of punishment and penalty were suggested. Most of all, rules and culture for fair trading should become more established in construction industry by preventing conflict among participants through active communication.

• Journal of Korean Philosophical Society
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• v.148
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• pp.183-211
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• 2018

Hyesim(慧諶) was an important figure that established a firm position of Suseonsa(修禪社), which was Jinul's Gyeolsadojang(結社道場), under the sponsorship of Choi Yi(崔怡)'s military regime. This paper reviews the background of "Ganbyeongron(揀病論)", in which Hyesim's Zen ideology is condensed, and its core content Sibjongbyeong(10 kinds of disease). With this, we can newly recognize following 5 facts: First, Sibjongbyeong occupied the most important position in Hyesim. It can be confirmed by the fact that Sibjongbyeong commonly occurred in the procedure that Hyesim was trusted by Jinul, in the "Ganhwagyeoleuiron(看話決疑論)" a Jinul's posthumous work published by Hyesim, and in "Ganbyeongron". Second, the publication of "Ganbyeongron" was not only for the systematic development of Ganhwa Gyeongjeol(看話 徑截) which Jinul had suggested but also for the consolidation of Hyesim's position in Suseonsa. Third, Hyesim wanted to establish the Ganhwa Gyeongjeol which Jinul had proposed through "Ganbyeongron". Fourth, the result of "Ganbyeongron" was to generalize the enlightenment suggested by Jonggo and Jinul in the practical aspect. Fifth, the generalization of enlightenment was not independent from the demands of the time that Choi Yi's military regime had asked. With this research approach, we can establish a clearer understanding about the "Ganbyeongron", Sibjongbyeong, and the Zen Buddhist aspects of early Suseonsa Era.

• 한국사회정책
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• v.25 no.3
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• pp.279-303
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• 2018

Since the introduction of the Riester Pension Scheme, the controversy has continued in the policy studies and the political debates. This study evaluates the achievements and limitations of the German Riester pension scheme and tries to derive policy implications for South Korea. As a result of the analysis, the most worthwhile achievement of the Riester Pension is to strengthen the role of the private pension schemes. Unlike other private pension schemes, it included a large part of lower income households. It also opened a new perspective of utilizing private pension schemes to accomplish the goals of the family policy. Despite these attainments, it does not reach the promised coverage rate. It also was revealed that the higher income households have concluded more Riester Pension Contracts than the targeted lower-income households. Due to high administration fee and incomplete information problems, benefit levels are supposed to be much lower than expected. It concludes, above all, despite some achievements, the Riester Pension Scheme will not fill completely the gap of old age income security caused by the reduction of the public pension system. The German case provides fruitful lessons for Korea. The introduction of a subsidized personal pension scheme in South Korea can be realized only when some prerequisites would be satisfied such as the consolidation and maturing of public pension schemes and the strengthening of the transparency in the private pension market.

• Journal of Navigation and Port Research
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• v.43 no.4
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• pp.256-263
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• 2019

The trade volume of Northeast Asian countries is increasing and with the advent of the 4th revolutionary era, minimizing the logistics costs of firm is becoming an important competitive factor. With respect to this, in 2006, the government introduced a certified Integrated logistics firm system to improve the competitiveness of local logistics firms and reduce the logistics costs of firms. They argued that the certified Integrated logistics firm system increased the reliability of logistics firms and increased the efficiency of the logistics industry. On the other side, they argue that the system puts a burden on firms and becomes a big business-oriented market consolidation. This study analyzed the efficiency of Warehousing firms using DEA model. The CCR, BBC efficiency and RTS (return to scale) of 15 Warehousing firms were evaluated. This study also suggested the Warehousing firms which can be benchmarked based on analyzed information.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.409-418
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• 2019

Debris flows occur in mountainous areas due to heavy rains resulting from climate change and result in disasters in the downstream area. The purpose of this study is to estimate the impact force of a debris flow when a check dam according is installed in various locations in the channel of a highly mountainous area. A Finite Differential Element Method (FDM) model was used to simulate the erosion and deposition based on the equation for the mass conservation and momentum conservation while considering the continuity of the fluid. The peak impact force from the debris flow occurred at 0 to 5 sec and 15 to 20 sec. When the supplied water discharge was increased, greater peak impact force was generated at 16 to 19 sec. This means that when increasing the water supply, the velocity of the debris flow became faster, which results in increased energy of the consolidation between the particles of the water and the sediment made. If a number of check dams were to be set up, it would be necessary to investigate the impact force at each location of the check dam. The results of this study could provide useful information in predicting the impact force of the debris flow and in installing the check dams in appropriate locations.

• Journal of the Korean GEO-environmental Society
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• v.12 no.6
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• pp.25-34
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• 2011

Dredged and reclaimed ground in progress at the West Coast has a high content of coarse particles. There will be different behaviors depending on the location of outlet and engineering properties of soil when its ground is dredged by a pump. Therefore, the experiments were conducted that were manufactured about the chamber equipment of length 2,650mm, width 770mm, height 735mm, experimented step filling method and water content about 300%, 500% and 700% respectively with SM and ML samples in order to realize segregating sediment characteristics of dredged ground with changing much fine. With results of analysis, ML sample by higher initial water content was reached to the period of complete sedimentation and coefficient of sedimentation consolidation increased with increases of diffusion distance. SM samples showed behavior of coarse soil with diffusion distance 120cm, diffusion distance of more than 120cm showed a similar tendency with ML sample under the influence of fines. In ML sample, it could be also found that lower depth and the more increasing diffusion distance increase in percentage of sieve #200 but water content decreases. In SM sample, it could be also found that coarse soil was piled at near the diffusion distance zone but fine soil was piled at the far diffusion distance zone and prominent difference showed between percentage of sieve #200 and water content(%) by boundary point 120cm~160cm of both samples. Also, shear strength was expressed ML-maximum 2.97kPa, SM-maximum 10.2kPa with diffusion distance.

• Geomechanics and Engineering
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• v.25 no.3
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• pp.207-219
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• 2021

Several additives are used to enhance the geotechnical properties (e.g., shear wave velocity, shear modulus) of soils to provide sustainable, economical and eco-friendly solutions in geotechnical and geo-environmental engineering. In this study, piezoelectric ring actuators are used to measure the shear wave velocity of unreinforced, fiber, cemented, and fiber reinforced cemented Toyoura sand. One dimensional oedometer tests are performed on medium dense specimens of Toyoura sand-cement-fiber-silica flour mixtures with different percentages of silica flour (0-42%), fiber and cement (e.g., 0-3%) additives. The experimental results indicate that behavior of the mixtures is significantly affected by the concentration of silica flour, fiber and cement additives. Results show that with the addition of 1-3% of PVA fibers, the shear wave velocity increases by only 1-3%. However, the addition of 1-4% of cement increases the shear wave velocity by 8-35%. 10.5-21% increase of silica flour reduces the shear wave velocity by 2-5% but adding 28-42% silica flour significantly reduces the shear wave velocity by 12-31%. In addition, the combined effect of cement and fibers was also found and with only 2% cement and 1% fiber, the shear wave velocity increase was found to be approximately 24% and with only 3% cement and 3% fibers this increased to 35%. The results from this study for the normalized shear modulus and normalized mean effective stress agree well with previous findings on pure Toyoura sand, Toyoura silty sand, fiber reinforced, fiber reinforced cemented Toyoura sand. Any variations are likely due to the difference in stress history (i.e., isotropic versus anisotropic consolidation) and the measurement method. In addition, these small discrepancies could be attributed to several other factors. The potential factors include the difference in specimen sizes, test devices, methods of analysis for the measurement of arrival time, the use of an appropriate Ko to convert the vertical stresses into mean effective stress, and sample preparation techniques. Lastly, it was investigated that there is a robust inverse relationship between α factor and 𝞫₀ exponent. It was found that less compressible soils exhibit higher 𝜶 factors and lower 𝞫₀ exponents.

• Journal of Korea Port Economic Association
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• v.39 no.1
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• pp.149-172
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• 2023

In the Northeast Asian region, including Korea, China, and Japan, with rapid economic growth since the 1990s, intra-regional oil logistics has been increasing. Under such external circumstances, Korea has been pursuing a policy to become a Northeast Asian petroleum logistics hub since the mid-2000s. In order to become a Northeast Asian logistics hub, it is important to establish and promote a business model to promote the value-added oil logistics business. This study aims to propose policies and practical implications for increasing petroleum logistics by analyzing Korea's petroleum logistics business model in Northeast Asia. The results of case analysis through interviews with 23 tank terminal companies are as follows. First, most of the oil storage tank terminal companies interviewed are conducting value-added petroleum logistics such as blending, breaking bulk, and consolidation etc. Second, value-added petroleum logistics is caused by an imbalance in supply and demand among neighboring countries in Northeast Asia. In particular, there is a high demand for breaking bulk and blending connecting Japan, Oceania, the United States, and South America. Third, it is necessary to promote the promotion of value-added logistics by improving infrastructure, institutions, and regulations in response to the demand for value-added petroleum logistics, which will greatly contribute to Korea's policy for being Northeast Asian oil hub.

• Journal of the Korean Geosynthetics Society
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• v.22 no.3
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• pp.47-59
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• 2023

In this research, laboratory tests were conducted on clayey sand (SC) to analyze its physical properties, compaction/permeability characteristics, and stress-strain behavior. The main objective was to determine the transitional fines content at which the mechanical properties of sand transition to those of clay, resulting in a change in the geotechnical behavior of the material. Additionally, to assess the practical applicability of SC soil, field data from a soft ground improvement site with significant settlement issues were collected. The settlement characteristics derived from laboratory tests and numerical simulations were then compared and analyzed in relation to the actual settlement data obtained from the field, aiming to evaluate the suitability of the SC soil as a compaction target layer. The laboratory tests and compaction analysis showed that the SC soil exhibited a distinct change in mechanical properties, shifting from sandy behavior to clayey behavior when the fines content exceeded 25%. This transition in mechanical behavior was found to be closely correlated with the content of clay particles within the material. Through numerical simulations of the soft ground site, it was verified that the use of clayey sand with a fines content exceeding the transitional level as a compaction target layer resulted in settlements that closely aligned with the measured settlements, with an average agreement of 91.2%. Based on these findings, it is deemed advisable to incorporate clayey sand with a fines content exceeding the transitional level as part of the compaction target layer in the design of soft ground improvements.

• Journal of the Korean Geotechnical Society
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• v.23 no.3
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• pp.25-40
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• 2007

Excessive earth pressure is one of the major mechanical factors in the deformation and damage of Cut-and-Cover Tunnel lining in shallow tunnels and portals of mountain tunnels (Kim, 2000). Excessive earth pressure may be attributed to insufficient compaction and consolidation of backfill material due to self-weight, precipitation and vibration caused by traffic (Komiya et al., 2000; Taylor et al., 1984; Yoo, 1997). Even though there were a lot of tests performed to determine the earth pressure acting on the tunnel lining, unfortunately there were almost no case histories of studies performed to determine remedial measures that reduce differential settlement and excessive earth pressure. In this study the installation of geotextile mat was selected to reduce the differential settlement and excessive earth pressure acting on the cut-and-cover tunnel lining. In order to determine settlement and earth pressure reduction effect (reinforcement effect) of geotextile mat reinforcement, laboratory tunnel model tests were performed. This study was limited to the modeling of rigid circular cut-and-cover tunnel constructed at a depth of $1.0D\sim1.5D$ in loose sandy ground and subjected to a vibration frequency of 100 Hz. Model tests with varying soil cover, mat reinforcement scheme and slope roughness were performed to determine the most effective mat reinforcement scheme. Slope roughness was adjusted by attaching sandpaper #100, #400 and acetate on the cut slope surface. Mat reinforcement effect of each mat reinforcement scheme were presented by the comparison of earth pressure obtained from the unreinforced and mat reinforced model tests. Soil settlement reduction was analyzed and presented using the Picture Analysis Method (Park, 2003).