• Journal of Korea Water Resources Association
• /
• v.41 no.12
• /
• pp.1219-1230
• /
• 2008

Stream inflows induced by flood runoffs have a higher density than the ambient reservoir water because of a lower water temperature and elevated suspended sediment(SS) concentration. As the propagation of density currents that formed by density difference between inflow and ambient water affects reservoir water quality and ecosystem, an understanding of reservoir density current is essential for an optimization of filed monitoring, analysis and forecast of SS and nutrient transport, and their proper management and control. This study was aimed to quantify the characteristics of inflow density current including plunge depth($d_p$) and distance($X_p$), separation depth($d_s$), interflow thickness($h_i$), arrival time to dam($t_a$), reduction ratio(${\beta}$) of SS contained stream inflow for different flood magnitude in Daecheong Reservoir with a validated two-dimensional(2D) numerical model. 10 different flood scenarios corresponding to inflow densimetric Froude number($Fr_i$) range from 0.920 to 9.205 were set up based on the hydrograph obtained from June 13 to July 3, 2004. A fully developed stratification condition was assumed as an initial water temperature profile. Higher $Fr_i$(inertia-to-buoyancy ratio) resulted in a greater $d_p,\;X_p,\;d_s,\;h_i$, and faster propagation of interflow, while the effect of reservoir geometry on these characteristics was significant. The Hebbert equation that estimates $d_p$ assuming steady-state flow condition with triangular cross section substantially over-estimated the $d_p$ because it does not consider the spatial variation of reservoir geometry and water surface changes during flood events. The ${\beta}$ values between inflow and dam sites were decreased as $Fr_i$ increased, but reversed after $Fr_i$>9.0 because of turbulent mixing effect. The results provides a practical and effective prediction measures for reservoir operators to first capture the behavior of turbidity inflow.

• Journal of Music and Human Behavior
• /
• v.2 no.2
• /
• pp.1-14
• /
• 2005

This research was to study the behavior of listening music, music preference, meaning and role of music. The interviewees were 158 male/female students of high school in second level. This research had a interview which is composed with 7 multiple choice-questions and 1 short answer-question. In result, in the question of 'The average time of listening music', the most students(64, 41.8%) answered '1~2hours', the secondary, '2~3hours' which was 32.(20.9%) In the next question, 'The preference of music genre', 87students(56.8%) answered 'Korean pop and rock', 'American pop' was 11.1% each. Regarding 'The favorite mood of music', 50.3% of students answered 'Mellow songs, 24.8% of students answered 'Jaunty songs'. Regarding 'The social factor of listening music', more than half students(56.7%) agreed that friends or something like that may affect their music preference. Likewise, 51.6% agreed that their temper or character may affect their music preference. They answered that they enjoy the music usually when they take a rest(30.1%), when in moving(24.3%). Lastly, it said 'The meaning of music' is mostly 'Getting rid of stress and Refresh'(25.1%). And 'Calmness', 'Comfort' was 21.8%. The music especially to students means 'Emotional exit'. The music which can enable them to express their feelings is related with feeling and emotion deeply. And emotional factors like stress, depression, anxiety becomes the main reason of accepting the music meaningfully. In conclusion, This research says that they experience positive feelings and express emotions through music which enables them to understand fully their feelings and emotions.

• Atmosphere
• /
• v.22 no.4
• /
• pp.489-497
• /
• 2012

Recently released a top secret document explicitly shows that the early development plan for an earth observation satellite in the USA has a hidden and more important purpose for a concept of 'free space' than the scientific purpose. At that time, the hidden and secret concept imbedded within the early space development plan prevail other national policies of the USA government for purpose of the national security. Under these circumstances, it is quite reasonable to accept a possibility that the meteorological satellites which play a key role in the every area of meteorology and climatology was also born for the hidden purposes. Even it is so, it is quite amazing that the first meteorological satellite is launched in the USA despite of the facts that the major users of the meteorological satellites were not very enthusiastic with the meteorological satellite and the program was not started as a formal meteorological satellite project. This was only possible because of the external socio-political impact caused by the successful launch of the Russian Sputnik satellite and a few key policy developers who favored the meteorological satellite program. It is also interesting to note that the beginning of the first Korean meteorological satellite program was initiated by a similar socio-political influence occurred by the launch of a North Korean satellite.

• Clinical and Experimental Pediatrics
• /
• v.53 no.3
• /
• pp.300-306
• /
• 2010

Purpose : Recent changes in the population structure of Korea, such as rapid decline in birth rate and exponential increase in old-aged people, prompted us to prepare a new health improvement program in children and adolescents. Methods : We reviewed current health screenings applied for children and adolescents in Korea and other developed countries. We collected and reviewed population-based data focused on mortality and morbidity, and other health-related statistical data. We generated problem lists in current systems and developed new principles. Results : Current health screening programs for children and adolescents were usually based on laboratory tests, such as blood tests, urinalysis, and radiologic tests. Almost all of these programs lacked evidence based on population data or controlled studies. In most developed countries, laboratory tests are used only very selectively, and they usually focus on primary prevention of diseases and health improvement using anticipatory guidance. In Korea, statistics on mortality and morbidity reveal that diseases related to lifestyle, such as obesity and metabolic syndrome, are increasing in all generations. Conclusion : We recommend a periodic health screening program with anticipatory guidance, which is focused on growth and developmental surveillance in infants and children. We no longer recommend old programs that are based on laboratory and radiologic examinations. School health screening programs should also be changed to meet current health issues, such as developing a healthier lifestyle to minimize risk behaviors—or example, good mental health, balanced nutrition, and more exercise.

• Journal of Biomedical Engineering Research
• /
• v.25 no.1
• /
• pp.11-19
• /
• 2004

Stage 1 sleep provides important information regarding interpretation of nocturnal polysomnography, particularly sleep onset. It is a short transition period from wakeful consciousness to sleep. Lack of prominent sleep events characterizing stage 1 sleep is a major obstacle in automatic sleep stage scoring. In this study, we attempted to utilize simultaneous EEC and EOG processing and analyses to detect stage 1 sleep automatically. Relative powers of the alpha waves and the theta waves were calculated from spectral estimation. Either the relative power of alpha waves less than 50％ or the relative power of theta waves more than 23％ was regarded as stage 1 sleep. SEM (slow eye movement) was defined as the duration of both eye movement ranging from 1.5 to 4 seconds and regarded also as stage 1 sleep. If one of these three criteria was met, the epoch was regarded as stage 1 sleep. Results f ere compared to the manual rating results done by two polysomnography experts. Total of 169 epochs was analyzed. Agreement rate for stage 1 sleep between automatic detection and manual scoring was 79.3％ and Cohen's Kappa was 0.586 (p＜0.01). A significant portion (32％) of automatically detected stage 1 sleep included SEM. Generally, digitally-scored sleep s1aging shows the accuracy up to 70％. Considering potential difficulties in stage 1 sleep scoring, the accuracy of 79.3％ in this study seems to be robust enough. Simultaneous analysis of EOG provides differential value to the present study from previous oneswhich mainly depended on EEG analysis. The issue of close relationship between SEM and stage 1 sleep raised by Kinnariet at. remains to be a valid one in this study.

• Journal of Korean Society of Forest Science
• /
• v.90 no.5
• /
• pp.608-618
• /
• 2001

To understand the weathering processes of the soil by submicroscopic method is very important to realize the properties of the soils. In this study soil formation processes show every steps to the changes in chemical and mechanical properties and the submicroscopic characteristics of soil weathering on the profiles of forest soils derived from granite in southern part of Korea. Fecal pellets(SEM) are given a full detail of the positive activities of the forest soil animals; mainly invertebrates in the O horizon and the E horizon. External shapes of fecal pellets have been divided into five groups : spherical, ellipsoidal, cylindrical, platy and threadlike. But doughnutlike form of fecal pellets is observed in this study. The soluble and suspended materials in the soils move downwards by percolation from the A horizon to the B or the BC horizons, and result in the illuviation cutans(SEM) on the ped surface of the lower horizon and deposited stack of kaolinite. Illuviated cutans are deposited on the ped surface even in the depth of 312cm in the BC horizon as well as the Bt horizon and comprise of fine silt, coarse clay and fine clay. A lot of halloysites are observed on the cutan surface. Halloysite formation from feldspars has been well known but a lot of hallyosite formation are observed in this study. The formation were predicted by Jackson(1962), inferred by Wada and Kakuto(1983a, b) and proved evidently by Cho and Mermut(1992a, b). This also suggests that halloysites in the soils derived from granite are formed a lot from ferruginous chlorites. The release of Fe from the chlorite structure are significant pedogenic processes and newly formed Fe oxides imparted a red color to the soils. The iron oxides particles, which are ejected and recrystalized, aggregate thickly on the edge of the ferruginous chlorites, and this indicates the release of structural Fe from weathered chlorites. Hematites and goethites are frequent in the fine clay in this soils.

• Geophysics and Geophysical Exploration
• /
• v.9 no.4
• /
• pp.271-278
• /
• 2006

Investigations of underground cavities are required to provide useful information for the reinforcement design and monitoring of the ground subsidence areas. It is, therefore, necessary to develop integrated geophysical techniques incorporating different geophysical methods in order to accurately image and to map underground cavities in the ground subsidence areas. In this study, we conducted geophysical investigations for development of integrated geophysical techniques to detect underground cavities at the field test site in the ground subsidence area, located at Yongweol-ri, Muan-eup, Muan-gun, Jeollanam-do. We examined the applicability of geophysical methods such as electrical resistivity, electromagnetic, and microgravity to cavity detection with the aid of borehole survey results. The underground cavities are widely present within the limestone bedrock overlain by the alluvial deposits in the test site where the ground subsidences have occurred in the past. The limestone cavities are mostly filled with groundwater or clays saturated with water in the site. The cavities, thus, have low electrical resistivity and density compared to the surrounding host bedrock. The results of the study have shown that the zones of low resistivity and density correspond to the zones of the cavities identified in the boreholes at the site, and that the geophysical methods used are very effective to detect the underground cavities. Furthermore, we could map the distribution of cavities more precisely with the study results incorporated from the various geophysical methods. It is also important to notice that the microgravity method, which has rarely used in Korea, is a very promising tool to detect underground cavities.

• Korean Business Review
• /
• v.14
• /
• pp.1-30
• /
• 2001

To prevent the VAT evasion and to form a sound VAT paying culture, we can draw the policy directions for government as follows: First, it is necessary to strengthen the tax supervision of small business and the administration of tax sources of cash-income industry. Second, the tax-deductible rate of the received tax invoices should be increased in a short-term base, and a simplified taxation system should be abolished in a long-term base. Third, in cases a trader has not received a tax invoice, an additional tax should be applied. Forth, to issue the tax invoice faster and conveniently, it is requested to introduce a new system which issues electronic card of registration when a businessman applies for his/her business registration. Fifth, to make tax standard transparent, it is desirable to punish the violator, relating to credit card regulations, stricter than present and to enforce the electronic bookkeeping. Sixth, for the reduction of noncompliance rate and creating a climate for autonomous, faithful tax return, it is necessary to expand and intensify tax investigation. And also it is necessary to make the level of penalty tax higher up and the level of criminal punishment less down, to keep up tax audit coverage. Seventh, a trader who is eligible for simplified taxation, whose tax base is under 12,000 thousand won, should not be required to pay the value added tax. But it is desirable to cut down them for the fairness of tax burden. Eighth, the effective date of the revised tax law should be fixed. Ninth, it is necessary to reinforce publicity and to educate on tax system and administration, for reducing tax evasion or tax avoidance and encouraging faithful tax return. Tenth, as the tendency of VAT evasion of distribution industry turns out to be the highest, it is requested not only to intensify tax administration on them but also to establish system and incentives, for introducing information system in distribution industry(introducing POS system, computerization of transaction record, establishing EDI between traders).

• The Korean Journal of Financial Management
• /
• v.25 no.4
• /
• pp.25-51
• /
• 2008

In this paper, we analyse empirically the fixed asset investment smoothing of working capital of firms listed on Korea Securities Market. The main results of this study can be summarized as follows. Firms will seek to lower long-term cost by smoothing fixed asset investment and maintaining stationary investment with working capital. Working capital is not only an important use of fund, but also a source of liquidity that should be used to smooth fixed asset investment relative to cash flow shocks if firms face financial constraints. Working capital investment is more sensitive than fixed asset investment to cash flow fluctuations. If firms face financial constraints, working capital investment will compete with fixed asset investment for the limited pool of available cash flows. So, fixed asset investment will have negative relationship with working capital investment. However, criticism that the positive correlation between cash flows and fixed asset investment could arise simply because cash flows is proxy variable for investment demand. Finally, controlling for the fixed asset investment smoothing effects of working capital results in a much larger estimate of the long run impact of financial constraints. Financial constraints is measured by dividend payout ratio and market access level. Fazzari et al. (1988), Fazzari and Petersen (1993), and Faulkender et al. (2008) emphasize that low dividend firms or market unaccessible firms are more likely to face financial constraints, and rarely make use of new equity issuing. The results from empirical analysis show that financial constraints can be better explained using 'adjustment cost' concept. Specifically, the results show that financial constraints exist and that in order to measure financial constraint effects more succinctly, fixed asset investment smoothing effects with working capital should be considered.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.39 no.2
• /
• pp.103-112
• /
• 2011

The purpose of this study is to specify the prior eco-preserve zone by establishing the eco-landscape unit on the stream corridor and evaluating the stream ecosystem in the dam basin. The fundamental ecological data was surveyed and collected through "the ecosystem project on Yongdam multipurpose dam watershed" from 2008 to 2009. The Yongdam Dam Watershed has several streams, Jujacheon, Jeongjacheon and Guryangcheon, of which the area is $930km^2$, stretching to Jinangun, Jangsugun and Mujugun Jellabukdo. In spite of being used for drinking purpose, the dam water quality and ecosystem is threatened by in-watershed pollution produced by development, golf course grounds and sports complex, etc. The landscape unit of stream corridor was zoned across by 250m, 500m, and 750m from the vicinity line of stream, which was decided to the accuracy of mapping and surveying. Types of evaluation are the Stream Corridor Evaluation(SCE) and the Vegetated Area Evaluation(VAE). In the process of SCE, several indices were analysed, fish species diversity, species peculiarity, and stream naturality. Indices for VAE were forest stand map, vegetation protection grade, species diversity and peculiarity for wild bird and mammal life. The importance of the ecological items is categorized into three levels and overlapped for specifying the prior preserve zone. The area at which legally protecting species appeared is categorized as absolute preserve area. This study might be meaningful for proposing the evaluation process of a stream corridor ecosystem, which can synthesize a lot of individual ecological surveys. We hope further research will be actively performed about the ecotope mapping which is based on a individual wildlife territory and habitats and also their relationships.