• Journal of Korean Society for Geospatial Information Science
• /
• v.14 no.2 s.36
• /
• pp.89-94
• /
• 2006

Forest damage is a worldwide issue and specially, a forest fire involves damage to itself and causes secondary damage such as a flood etc. However, actually, clear analysis on forest fire damage can be hardly conducted due to difficulty in approaching a forest fire and quite a long period of time for analysis. To overcome such difficulty, recently, forest fire damage has been actively investigated with satellite image data, but it is also difficult to obtain satellite image data fitted to the time a forest fire occurred. In addition, it is burdensome to verify accuracy of the obtained image. Therefore, this study was attempted to look into the damaged districts from forest fires by reference to spectroradiometric characteristics of the obtained vegetation with a spectroradiometer as preliminary work to use satellite image data. To begin with, the researcher analyzed the field survey data each measured 3 months and 6 months after occurrence of a forest fire by judging the extent of the damage through visual observation and using a spectroradiometer in order to investigate any potential errors arising out of one-time visual observation. Besides, in this study, groups showing possibilities that trees might be restored to life and wither to death could be classified on the sampling points where forest fire damage is minor.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.35 no.3
• /
• pp.282-286
• /
• 1990

Currently, mechanization and automation have been introduced into rice harvest and drying process due to the shortage of man power. After rice cultivars, Chucheong and Milyang #23 were cutted with manual method (H1) or harvested with combine (H2), the threshed grain were dried in natural sun-drying (D1), in natural air in-bin system (D2), or in contineous hot-air drier (D3). We have evaluated grain losses, operation hour, and grain quality on each harvest and drying methods. Shattering loss during harvesting with combine was not dirfered significant from that of manual method, but threshing loss was 1.2% higher in combine harvest than in manual. Operation hours required for combine harvest was 3.5 times faster than for manual, even without head threshing. There was a significant difference bel ween cultivars in harvesting loss, which Milyang #23, a Tongil rice had two times more grain loss than Chucheong, a Japonica rice. Drying hours required to reduce to 14% grain moisture content were ten days for H1D1, 5-9 days for H2 D1, 2-3 days for H2D2, and only 15 hours for H2D3, respectively. In grain quality, complete grain ratio after dehulling was decreased about four percent in H2D3 compared to H1D1. while it was lower in Milyang #23 than in Chucheong, Hot-air drier increased occurence of cracked and broken grain. Combine harvest increased significantly these incomplete grain ratio of :Milyang #23, but not Chucheong.

• Journal of agriculture & life science
• /
• v.50 no.1
• /
• pp.117-124
• /
• 2016

Researches on soil microbial community are increasing to assess ecosystem responses to anthropogenic disturbances and to provide an indicator of ecosystem recovery. Microbial communities are able to respond more rapidly to environmental changes than plants and therefore they may provide an early indication of the ecosystem recovery trajectory. This study was conducted using 16S rRNA gene pyrosequencing of soil samples to compare soil bacterial community composition between artificially covered soils of the Baedudaegan ridgeline and their adjacent forest soils in two restoration project sites, Ihwaryeong and Yuksimnyeong, which were completed in 2012 and 2013, respectively. Richness of the Phylum level was 29.3 in Ihwaryeong and 32.3 in Yuksimnyeong. Significant difference in the richness between artificial restored soils and adjacent forest soils(p<0.01) was observed, however no significant difference was observed for site location and soil depth. Acidobacteria(37.3%) and Proteobacteria(31.1%) were more abundant than any other phylum in collected soil samples. Also, we found the significant difference in the relative abundance of the two abundant phyla between artificially restored soils and their adjacent forest soils (Proteobacteria, 38.1% in restored soils vs 24.2% in adjacent forest soils, p<0.01; Acidobacteria, 55.4% in restored soils vs 19.2% in adjacent forest soils, p<0.001). The results support the previous researches indicating that soil bacterial community composition is affected by nutritional status of soils and that Acidobacteria is also strongly influenced by pH, thus favoring soils with lower pH. This study could be utilized to monitor and evaluate restoration success of forest soil environment quantitatively.

• Korean Journal of Ecology and Environment
• /
• v.57 no.3
• /
• pp.169-188
• /
• 2024

Recently, Korean government has incorporated the assessment and restoration of river continuity as a key component of its integrated water management policy. While, methodologies for evaluating discontinuities and degradation, as well as the procedures for assessment and restoration, have been developed and proposed, there is a need for further improvement. Therefore, further research is required to establish a conceptual framework for continuity specific to domestic river ecosystems and to formulate appropriate assessment methods and restoration strategies. In this study we conduct a comparative analysis of the concepts, restoration approaches, and comprehensive evaluation methods for river continuity as proposed by Japan, the United States, and the European Union (EU), all of which have long-standing frameworks for river continuity assessment and restoration projects. Each country demonstrates distinct objectives and guidelines: Japan emphasizes habitat continuity within the context of river and watershed continuity, the United States integrates continuity as a tool for watershed management, and the EU prioritizes biodiversity conservation by advocating for the removal of artificial barriers and promoting the restoration of free-flowing rivers (FFR). By investigating these international examples, this study provides insights that can guide the development of long-term strategies and evaluation criteria for securing aquatic ecosystem continuity in Korea.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.2 no.4
• /
• pp.1-10
• /
• 1998

The magnitudes of historical earthquake records related with house collapses are estimated considering the magnitude, epicentral distance, soil condition and aging of a house. Eighteen artificial time histories for magnitudes 6-8, epicentral distances 5 km-350 km and hard and soft soil condition were generated. Nonlinear dynamic analyses were performed for a traditional three-bay-straw-roof house. The aging effect of the house was modeled as such that the lateral loading capacity of wooden frames represented by hysteretic stiffness was decreased linearly with time. The house was idealized by one degree-of-freedom lumped mass model and the nonlinear characteristics of wooden frames were modeled by the Modified Double-Target mode. For far field earthquakes, minor damages were identified regardless of magnitude, soil condition and aging of the house. For intermediate field earthquake, earthquake magnitude greater than 6.5 caused severe damages in soil sites. For near field earthquake, severe damages occurred for magnitude greater than 6.5 regardless of soil condition and aging of the house. It is estimated that the magnitude of historical earthquakes is about 6.2. An empirical equation of magnitude-intensity relationship suitable to Korea is suggested.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.37 no.3
• /
• pp.293-300
• /
• 2013

This study used a water tank and wave maker to generate conditions similar to the real ocean environment. Given that the waves were properly generated in the water tank, a precise analysis indicated the quantitative value of the wave force acting on a body. A high-speed camera and wave-level gauge were used to measure the temporal wave motion and period. A series of artificial water waves were successfully generated using three different wave periods and amplitudes. Each of the waves captured by a high-speed camera was sinusoidal and did not maintain its shape properly without a wave absorber, but it was substantially improved and well shaped when the wave absorber was installed.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.11 no.1
• /
• pp.116-124
• /
• 2008

This study presents the application of multi-temporal and multi-scale panchromatic aerial photos for change detection in a small urban area. For aerial photos of the scale of 1:20,000 taken in 1987 and 1996 and the scale of 1:37,500 taken in 2000. Pre-processing that make the same conditions to all of the aerial photos was carried out through geometric correction, registration, contrasting, resamplimg, and mosaicking and then change detection were carried out respectively by image differencing and image ratio techniques. As a result, the change of urban features and landcover were able to be detected from panchromatic aerial photos that is single-band images and then the detected change results were compared between both techniques.

• Korean Journal of Veterinary Research
• /
• v.38 no.4
• /
• pp.784-792
• /
• 1998

This study was conducted to select resistant chicken-line between Brown and White layer lines against Salmonella gallinarum infection. The Brown and White layer chickens allocated into different age groups were inoculated with S gallinarum (WJO-126) either orally($1{\times}10^7cfu$) or intramusculaly($5{\times}10^6cfu$) and clinical observations were made for 2 weeks. All dead birds were necropsied and culture was made to recover the inoculated organinsm from liver, spleen, brain, bone marrow and cecal contents. Serum was isolated from all live birds after 2 weeks experiment and these birds were also necropsied and cultured to reisolate S gallinarum. The brown layers showed very high mortality to S gallinarum infection regardless of their ages and routes of inoculation, while white layers did not shown any mortality by the direct effects of S gallinarum. The mortality rate of 2 week old brown layers, in particular, were 82.6% (19/23) in peroral group and 86.9% in intramuscularly inoculated group, while those of white layer groups were only 0.0% in both groups. S gallinarum could be reisolated from all dead birds, especially, from liver and spleen. This result was inferred that the organism is highly invasive on the chicken. The intramuscularly challenged birds showed more seropositive-reactors(86.9%) than orally inoculated groups(61.9%). The overall results of present study suggested that white layers are much more resistant than brown layers against the experimental infection of S gallinarum and shown experimentally that resistance to S gallinarum is a characteristic of the White-line layers.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.18 no.3
• /
• pp.163-171
• /
• 1998

Near/far field length and directivity of transducers were investigated for the improvement and evaluation of the detectability of flaws in a disc. The reference block is fabricated for the disc of stage 6 in Yonggwang unit 1. The near/far field and directivity of an ultrasonic transducer with the center frequency of 5MHz were calculated for the inspection of the disc. These values showed good agreements with the experimental results. In the system composed of a wedge and a disc, those are evaluated theoretically and experimentally for the specimen with the artificial flaws of the size 2mm and 4mm and an ultrasonic transducer with the center frequency 5MHz and diameter 0.5inch. The detectability of keyway-flaw and detectable region for inspection were evaluated by using both tangential $45^{\circ}$ and $90^{\circ}$ transducers located at the distance of 53mm and 75mm from the disc hub, respectively.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.18 no.5
• /
• pp.365-372
• /
• 1998

The method of measuring the nonlinear effect of ultrasonic waves is suggested as a new approach for the effective evaluation of material degradation. In sonic wave propagation, the existence of nonlinear effect can be demonstrated by the generation of higher order harmonic waves. So, at first, the mechanism of generating higher order harmonic components due to nonlinear effect was explained by using nonlinear elasticity. Next, we attempted to measure how much of the higher order harmonic component was generated in the degraded material. For this purpose, a measurement system mainly based on a high-powered nonlinear ultrasonic signal analysis system was constructed, and SS41 and SS45 specimen intentionally degraded by tensile load and fatigue load were tested. From the results, we confirmed that the measurement of nonlinear acoustic effect may be useful for the evaluation of material degradation.