• Journal of Agricultural Extension & Community Development
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• v.17 no.4
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• pp.685-716
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• 2010

The purposes of this study were to exploring the rural residents' satisfaction of living environment and social service. For these purpose we collected the data from the residents in rural area(1,000). The major findings of this study were as follows : First, the total satisfaction score is 58.9. The highest score group is housing and environment(69.9). And the lowest score group is cultural life and leisure environment. Various welfare services have been carried out for low income people, disabled people, old people, children and rural women within the social service system. But many respondents did not have chances to use social service because it was not efficiently provided many social services. So most of the residents in village wanted more welfare services. Second, the qualitative enhancement is more important than physical infrastructure expansion in order to improve rural settlement condition(housing quality, water supply and drainage, road and traffic system, medical care etc.)

• International Journal of Highway Engineering
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• v.8 no.2 s.28
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• pp.49-54
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• 2006

The purpose of this study was to determine the effect of expansion joint spacing (slab size) on the life cycle costs of owning Portland Cement Concrete (PCC) airfield pavements. Previous research has shown that slab size has a statistically significant impact on pavement performance. A probabilistic life cycle cost analysis was performed to determine if the effect of slab size on pavement performance would affect the total cost of ownership of PCC pavements. Data from 48 Pavement Condition Index (PCI) inspections of military and civilian airfields were used to develop probability-of-distress-by-condition curves, which were then used to develop probabilistic cost-of-repair-by-condition curves. A present worth life cycle cost analysis was then performed for various slab sizes, using construction costs, rehabilitation costs, and maintenance costs. Maintenance costs were determined by assuming a condition deterioration rate appropriate for each slab size and applying the cost-by-condition curves. The probabilistic cost-of-repair-by-condition curves indicated that smaller slabs are more expensive to repair on a unit cost basis. Life cycle cost analysis showed that larger slabs have a higher total cost of ownership than smaller slabs due to a faster rate of deterioration.

• The Korean Journal of Ceramics
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• v.4 no.4
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• pp.368-371
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• 1998

The work aims to evaluate the necessary physical properties of Abrasion Resistant Pavers designed for high volume pedestrian and road vehicle traffic and their influence on the selection of raw materials and ceramic processes. The pavers' specifications such as high strength and ware resistance demand a careful clay preparation, slow drying, slow firing and a balanced chemical and mineralogical composition. Therefore, developing abrasion Resistant Pavers in existing modern brickmaking plants, which are designed primarily for making bricks and pavers for domestic applications, has become a challenge for manufacturers and ceramic professionals. The significance of quality control and research and development in the production of these high class pavers is also emphasised in this work through the investigation of a paver that exhibits shrinkage cracking.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.505-515
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• 2009

In railway bridges, various loads including train load, transverse load and braking force are applied to continuous CWR or semi-continuous longer rail located on non-continuous bridge superstructures. The rail-girder interaction due to thermal expansion is also very complex in railway bridges because the thermal characteristics for each of the rails and girder are quite different. Recently, the bridge retrofits for seismic loads were performed on bridges not designed for these loads. These retrofits may however have limitations with respect to rail-girder interactions because, in general these retrofits address issues related only to seismic loads. In this study of seismic evaluations for railway bridges, the load effects on the bridge rails from the road beds through the continuous rails shall be considered. Practical methods will be proposed which will increase the railway stability. For this, rail-girder interaction analyses due to train loads, temperature changes and seismic loads were performed and the results reviewed from a practical point of view.

• Korean Journal of Environment and Ecology
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• v.37 no.6
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• pp.439-449
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• 2023

This study was conducted to verify the role of forest roads in the extinction of large forest fires in Korea. The study area was the forest fire-damaged area of Gangneung City, Gangwon Special Self-Governing Province, in April 2023, which is one of the areas with the highest road density among the major forest fires that have occurred so far. The scope of the forest fire damage area was confirmed through on-site survey, and the intensity of the fire was carried out through Sentinel-2 satellite imagery analysis. After that, the relationship between the damage range and intensity and the forest road was examined. About 59.6 km of roads were built within 50 m from the boundary of the forest fire damage area, which can easily access the entire 149.1 ha of forest fire damaged area. The road density is as high as 168.9 m/ha. All forests that were fragmented by roads were fragmented into 83 places, and all of these forests could be judged to have spread by spotting fire. As a result of analyzing the distribution of damage intensity by distance from the road to see the extent of damage according to the ease of access of fire extinguishing vehicles, it was confirmed that the proportion of areas with low-intensity damage has increased sharply even from 75 m or more away from the road. The results of analyzing the distribution of damage intensity by altitude to see the extent of damage according to the ease of access of fire extinguishing showed that the proportion of areas with low-intensity damage increased as the altitude increased, while the proportion of areas with damage of more than strong intensity decreased as the altitude increased. It was confirmed that there is no data that roads inside or adjacent to forests in the forest fire area of Gangneung City are effective in extinguishing forest fires. These results are contrary to the logic that increasing the road density in forests is effective in extinguishing forest fires. In the case of this fire area in Gangneung City, the road density is 43 times higher than the current road density in Korea claimed by the Korea Forest Service of 3.9 m/ha. This study suggests that roads can be a hindrance to extinguishing forest fires.

• Journal of Korean Society of Transportation
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• v.22 no.5
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• pp.139-149
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• 2004

As the expansion of road capacity has become impractical in many urban areas, congestion pricing has been widely considered as an effective method to reduce urban traffic congestion in recent years. The principal reason is that the congestion pricing may lead the user equilibrium (UE) flow pattern to system optimum (SO) pattern in road network. In the context of network equilibrium, the link tolls according to the marginal cost pricing principle can user an UE flow to a SO pattern. Thus, the pricing method offers an efficient tool for moving toward system optimal traffic conditions on the network. This paper proposes a continuous network design program (CNDP) in network equilibrium condition, in order to find optimal congestion toll for maximizing net economic benefit (NEB). The model could be formulated as a bi-level program with continuous variable(congestion toll) such that the upper level problem is for maximizing the NEB in elastic demand, while the lower level is for describing route choice of road users. The bi-level CNDP is intrinsically nonlinear, non-convex, and hence it might be difficult to solve. So, we suggest a heuristic solution algorithm, which adopt derivative information of link flow with respect to design parameter, or congestion toll. Two example networks are used for test of the model proposed in the paper.

• Journal of Navigation and Port Research
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• v.41 no.3
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• pp.155-164
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• 2017

While many countries are implementing various policies regarding the logistics network in Eurasia, China has presented "the Belt and Road" Initiative, a development strategy that focuses on connectivity and close cooperation between China and Eurasia. With more than 60 countries participating in the project, China is expected to have a major influence on logistical infrastructure development in Eurasia. This study analyzed the railway stations network using social network analysis (SNA) methodology. We collected data from major railway lines in Eurasia (TAR, TEN-T, TRACECA, GMS) and established a network of 994 railway stations in 65 countries. This study presented the general characteristics of major railway stations from the perspective of SNA and compared the Chinese network with Eurasian networks. To review the railway networks in China and Eurasia, the top 30 stations were selected based on degree centrality and betweenness centrality. Top "degree centrality" stations included Bangkok (Thailand), Tbilisi (Georgia), Baku (Azerbaijan), Kunming (China), and Bucharest (Romania). Top "betweenness centrality" stations were Baku and Alyat (Azerbaijan), Baoji and Turpan (China), Qarshi (Uzbekistan), and Kas (Turkey). In China, Kunming, Nanning, and Gejiu stations have higher degree centrality while betweenness centrality was higher in Baoji, Kunming, and Lanzhou stations. "The Belt and Road" project advocated by China envisions expansion of transportation infrastructure connections throughout Eurasia, but more emphasis is likely to be placed on connectivity that benefits China. In this regard, studies on key bases of international logistics need to consider relative significance within the Chinese network.

• Korean Journal of Environment and Ecology
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• v.21 no.3
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• pp.278-289
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• 2007

This study investigated species formation and their vegetation on the roadsides of 1100 Road and 5 16 Road in Hallasan National Park from August 2004 to December 2006 to provide basic data for distributional attribute of the naturalized plants. The vascular plants investigated on the roadsides of Hallasan National Park were found to be 62 families, 145 genera, 197 taxa in total, in which naturalized plants were recorded as 11 families, 29 genera, and 37 taxa. The floristic formation at 1100 Roadside was composed of Festuca arundinacea-Dactylis glomerata association, which was again divided into Trifolium pratense-Plantago lanceolata sub-association and Sasa quelpaertensis-Gleichenia japonica sub-association. The florisitic composition of the 5 16 Roadside was sorted as Festuca arundinacea-Dactylis glomerata association, Oplismenus undulatifolius-Potentilla fragarisiiforlia, elatior association, Ambrosia artemisiifolia, and etatior-Persicaria thunbergii association. Among the naturalized plants distributed at this area, the annual plant accounts for 51.4%[19 taxa] and the plant of European origin accounts for 70.3%[26 taxa]. As for the background of the introduction of these plants, the case of introduction for forage or a mixture with grain and for pasture was 35.1% and 21.6% respectively, showing higher introduction circumstances than others. As shown in the study, most of the roadsides were occupied by the naturalized plants- Festuca arundinacea and Dactylis glomerata association and various naturalized plants; thus we can assume that it's because Festuca arundinacea and Dactylis glomerata association were mostly used for re-vegetation of the destroyed areas due to road construction or expansion or road maintenance and improvement project.

• International Journal of Highway Engineering
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• v.13 no.3
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• pp.1-6
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• 2011

The possibility of ASR(alkali-silica reaction) for coarse aggregates had known to be low up to recently in Korea. But the distress of ASR was identified and reported by ASTM C 1260 test. The purpose of this paper was to identify the effect of environmental conditions on length expansion of mortar-bar by alkali-silica reaction with KS F 2546 and ASTM C 1260 test. The results of this study were as following; The result of KS F 2546 test for five kinds of aggregates shows that all of them are non-reactive. But that of ASTM C 1260 test shows that all of aggregates except Andesite-2 are over possible reactive because of environmental condition such as external alkali ion by 1N NaOH, high temperature and humidity. The result of variety of NaOH concentration on ASTM C 1260 using Siltstone indicates that length expansion rate increases highly as NaOH concentration increases. And, comparison results of KS F 2546 for Siltstone with that of 0.00N NaOH experiment indicates that length expansion rate increases as temperature and humidity increases.

• International Journal of Highway Engineering
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• v.11 no.2
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• pp.185-194
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• 2009

The autogenous shrinkage of high-performance concrete, including very-early strength latex-modified concrete(VES-LMC), is generally bigger than that of normal strength concrete because of the low water/cement ratio, high binder contents, and usage of superplasticizer. Mix. proportion of VES-LMC has low water/cement ratio(0.38), high cement content(390kg/m$^3$), and aid of latex(15% of cement weight). Thus, these factors of VES-LMC, rapid water self-dissipation and evaporation within 3 hours of concrete placement would increase the autogenous shrinkage. The purpose of this study was to evaluate the early-age shrinkage, thermal deformation and autogenous shrinkages of VES-LMC with retarder contents(retarder solids-cement ratio, by weight) using to secure working time in field. The experimental results showed that retarder contents do not affect of the maximum hydration temperature. Early-age expansion of VES-LMC was mostly caused by thermal expansion and partly by autogenous expansion. The autogenous shrinkage is decreased by increasing the retarder contents within this study. On the other hand, the usage of retarder should be decided carefully considering the field conditions because an excessive usage of retarder can cause handful early-age expansion.