• Korea journal of population studies
• /
• v.27 no.2
• /
• pp.1-34
• /
• 2004

최근 한국사회에서는 출산율의 저하로 인한 사회경제적 영향을 우려하여 대책방안을 강구하여야 한다는 논의가 증대되고 있다. 그런데 국가정책을 개발${\cdot}$추진하기 이전에 반드시 요구되는 것은 저출산 현상의 올바른 인식과 철저한 원인규명이다. 따라서 본 연구에서는 출산율 변화의 원인을 다각적으로 살펴보고, 향후 변화방향을 전망해 보고자 한다. 먼저 자녀출산의 변화를 결혼상태 변화와 유배우부인의 출산율 변화 부분으로 나누어 살펴본 결과, 과거와는 달리 최근의 출산율 저하는 유배우 부인에 의해서가 아니라 미혼자의 결혼연장 또는 독신생활에서 기인되는 것으로 나타났다. 이들 두 요인에 영향을 주는 변수로는 경기침체 및 직장불안정, 결혼가치관의 변화와 초혼연령의 상승, 자녀양육 관심증대, 자녀양육비 부담, 가정과 직장의 양립을 위한 사회적 인프라 부족, 여성의 자아욕구 및 사회참여 증대, 자녀효용가치 감소, 이혼 등 가족해체의 증대, 그리고 불임부부의 증대 등인 것으로 판단된다. 향후 출산율 변화를 전망해 보면, 저출산을 일찍 경험한 서구 선진국의 경우와는 달리 정책의 추진에 한계가 있어 선진국보다 더 낮은 출산율을 회복하는 데는 많은 어려움이 있을 것이라는 판단이다. 더군다나 젊은 미혼남녀의 가치관이 개인주의화 되는 경향이 있다는 점을 감안한다면 출산율 회복정책을 추진한다 하더라도 한계가 있을 수밖에 없을 것이다. 수년간 실시된 각종 실태조사를 분석한 결과에 의하면 현재의 경기침체가 회복될 경우 약 20%의 출산율 상승 가능성이 있으며, 이 때의 합계출산율은 약 1.43명 수준이 될 수 있을 것으로 예견된다. 또한 종합적 체계적 출산회복정책을 효과적${\cdot}$효율적으로 추진한다면 약 10년 후에는 합계출산율이 약 1.6 수준으로 회복될 것이라는 낙관적 견해를 가져본다. 그렇지만 정책의 강도에 따라서 회복수준은 현저하게 상이할 것이다.를 진단, 치료함에 있어 진행성 신질환의 가능성을 시사하는 예후인자가 없다면 신생검보다는 지속적이고 정기적인 추적관찰만으로도 충분할 것으로 생각된다도 등은 양군 사이에 유의한 차이가 관찰되지 않았다. 발견 당시 혈청 $C_3$치의 감소는 모두 11명(61.1%)에서 관찰되었는데, 증상군에서는 7명(87.5%), 집단뇨검사군에서는 4명(40%)으로 증상군에서 혈청 $C_3$치의 감소가 보다 현저하였다. 그러나 추적관찰 기간 동안 증상군에서는 7명 중 4명, 집단뇨검사군에서는 4명 중 1명에서 혈청 $C_3$치는 정상범위로 증가하여 최종 관찰시점에서는 6명 (33.3%)에서만 혈청 $C_3$치의 감소가 지속되고 있다. 혈청 $C_3$치의 감소를 보인 경우를 다시 병리조직학적 분류에 의해 세분하여보면 발병당시에는 I형 8명(61.5%), II형에 1명(100%), III형 2명(50%)에서 관찰되었는데, 최종 시점에서는 I형 4명(30.8%), II형 1명(100%), III형 1명(33.3%)이었다. 또한 증상군에서 세포성 반월체형성과 세뇨관위축의 빈도가 높았으며, 사구체 혈관벽 비후와 사구체 간질의 증가의 정도가 집단뇨검사군에 비해 통계적으로 유의하게 높았다. 결론: 무증상성 요이상을 가진 환자에서 신장조직검사 실시 후 MPGN으로 진단되는 증례가 증가하고 있고, 오히려 증상을 동반하는 경우보다 빈도가 증가한다는 사실은 집단뇨 검사에서 소변의 이상소견이 발견되어 신장 조직검사를 실시할 경우 혈청 $C_3$치의 감소 여부에 관계없이 MPGN도 진단적 고려 대상이 되어야 한다고 생각한다.신장 조직검사를 시행한 결과 진행성 경과를 취할 수 있는 막 증식성 사구체 신염과 매우 희귀한 증례인 신유전분증 등으로 진단됨으로써 지속성 단백뇨의 경우 정확 진단적 접근이 필수적임을 알 수

• Korean Journal of Food Science and Technology
• /
• v.33 no.6
• /
• pp.664-668
• /
• 2001

The physical and chemical stabilities of carthamin of red pigment from safflower petals were investigated at various conditions of pHs, temperatures, inorganic ions, sugars, light and polysaccharides. The half-life values at pH 3.0, 5.0, 9.0 and 11.0 were 5.3, 5.0, 11.0 and 45.0 h, respectively, at $25^{\circ}C$. Therefore, carthamin is unstable at acidic condition. Carthamin was red, orange and yellow at acidic, neutral and alkaline solutions, respectively. At pH 3.0, carthamin was thermally unstable and the half lives were 3.62, 9.05 and 48.2min at $90^{\circ}C$, $70^{\circ}C$ and $50^{\circ}C$, respectively. Among various inorganic ions, $Al^{3+}$ stabilized carthamin at acidic condition. At pH 5.0, carboxymethylcellulose prolonged the half-lives of carthamin at $25{\sim}90^{\circ}C$. Carthamin was very sensitive to light (20,000 lux) and the half-life was 2.32 min at pH 3.0.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.14 no.4
• /
• pp.143-154
• /
• 2012

As demand of water resources and attentions to changes in climate (e.g., due to ENSO) increase, long/short term prediction of precipitation is getting necessary in water planning. This research evaluated the ability of MM5 to predict precipitation in the Tampa Bay region over 23 year period from 1986 to 2008. Additionally MM5 results were statistically bias-corrected using observation data at 33 stations over the study area using CDF-mapping approach and evaluated comparing to raw results for each ENSO phase (i.e., El Ni$\tilde{n}$o and La Ni$\tilde{n}$a). The bias-corrected model results accurately reproduced the monthly mean point precipitation values. Areal average daily/monthly precipitation predictions estimated using block-kriging algorithm showed fairly high accuracy with mean error of daily precipitation, 0.8 mm and mean error of monthly precipitation, 7.1 mm. The results evaluated according to ENSO phase showed that the accuracy in model output varies with the seasons and ENSO phases. Reasons for low predictions skills and alternatives for simulation improvement are discussed. A comprehensive evaluation including sensitivity to physics schemes, boundary conditions reanalysis products and updating land use maps is suggested to enhance model performance. We believe that the outcome of this research guides to a better implementation of regional climate modeling tools in water management at regional/seasonal scale.

• Journal of Korean Association for Spatial Structures
• /
• v.8 no.3
• /
• pp.45-51
• /
• 2008

A single layer-latticed dome is advantageous for large span structures because it is very stiff despite the light weight of the structure itself. However, this structure becomes easily unstable during erection due to its large size. The Block method is popular with the large span structures. A partial block of the dome is fabricated on the ground and lifted by crane to a designated location of structures. The lifting point selection is very important to create a stable erection and to avoid buckling of members during the erection. The purpose of this study is to analyze the structural behaviors and buckling characteristics according to the lifting point of single-layer latticed domes with triangle network in order to take materials about the safe and economic erection. The conclusions are obtained as follow. 1) The buckling strength of the block part varies with the location of lifting points when it is erected. In case, the height of the dome is lower, the effort of buckling strength of the structure is higher. 2) In buckling strength, the effect of the lifting rope length is smaller than it of the lifting points change.

• Korean Journal of Medicinal Crop Science
• /
• v.5 no.2
• /
• pp.131-138
• /
• 1997

Campanulaceae having the most growing areas among medicinal crops cultivated in Korea occasionally failed to establish a reasonable standing in practice. The experiment was carried out to examine the effect of prechilling (0 : 4 : 8 days), light quality (red : white : dark) and daily irradiation hours (8 : 12 : 16) after sowing on seed germination and radicle elongation of Campanulaceae (Platycodon grandiflorum : Codonopsis lanceolata : C. pjlosula) to give an information on their earlier standing establishment. Mean germination rate of P. grandiflorum was the highest but that of C. pilosula was the lowest regardless of all the treatments. 12 hours irradiation or prechilling increased to 8 days enhanced their earlier or later germination, respectively. White light increased the rate of P. grandiflorum but alleviated that of C. lanceolata regardless of the daily irradiation hours. Although prechilling eliminated such effect of white light, light quality treatment effect on their mean germination rates was influenced by period after sowing, daily irradiation hours or prechilling. On the 9th day after sowing, C. lanceolata showed the greatest radicle length, and both daily 8 hours irradiation and 8 days prechilling enforced to elongate their radicles, while P. grandjflorum and C. lanceolata more lengthened their radicles in all prechilling treatments than in no chilling but C. pilosula showed the similar result only in the 8 days prechilling.

• Journal of the Korean Ceramic Society
• /
• v.40 no.11
• /
• pp.1067-1072
• /
• 2003

The electrical stability of the varistor ceramics composed of Zn-Pr-Co-Cr-Dy oxides-based varistors was investigated at 0.0∼2.0 mol% Dy$_2$O$_3$ content under DC accelerated aging stress. The ceramic density was increased up to 0.5 mol% Dy$_2$O$_3$ whereas further addition of Dy$_2$O$_3$ decreased sintered ceramic density. The density sailently affected the stability due to the variation of conduction path. The nonlinearity of varistor ceramics was greatly improved above 45 in the nonlinear exponent and below nearly 1.0 ${\mu}$A by incorporating Dy$_2$O$_3$. Under 0.95 V$\_$1mA/150$^{\circ}C$/24 h stress state, the varistor ceramics doped with 0.5 mol% Dy$_2$O$_3$ exhibited the highest electrical stability, in which the variation rates of varistor voltage, nonlinear exponent, and leakage current were -0.9%, -14.4%, and +483.3%, respectively. The variation rates of relative permittivity and dissipation factor were +7.1% and +315.4%, respectively. The varistors with further addition of Dy$_2$O$_3$ exhibited very unstable state resulting in the thermal runaway due to low density.

• Journal of Conservation Science
• /
• v.6 no.1 s.7
• /
• pp.31-60
• /
• 1997

Stone-cultural-properties, distributed in Naju, Hwasun and a part of Jangheung, have been investigated and studied on the characteristics, rock weathering and phases in the geological and conservational points of view. The properities involve pagoda and twelve stupas, four stone-buddha, three stone monuments, two stone-lantern, four stone-Jangseung, one and flag-pole. The rocks used are mainly pebble-bearing tuffaceous rocks of the Cretaceous age which are widely distributed in the area. However, granites are also used in some properties. These rocks are strongly influenced by weathering and pervasive moss. The mottled rock surfaces in some properties are in colors due to pervasive moss different. Parts of some cultural properties are broken which results in structurally unstable. Cultural properties in the area are relatively well conserved at the earth consolidated by ramming and by iron fence. However some cultural properties are partly repaired by using other hinds of rock phases which results in different colors in weathered rock surface. For conservation, rock phases, weathered surface colors, and relationships with original parts must be scientifically considered in repairment forward.

• The Journal of Engineering Geology
• /
• v.18 no.4
• /
• pp.459-470
• /
• 2008

Types of slope failure related to cut slope stability are interpreted through case analyses, and also factors affecting structurally controlled instability investigated, which are developed by geologic structures along a national road No. 25 across the Cheongwon and Boeun-Guns, Chungbuk. Engineering properties such as orientation, persistence, roughness and uniaxial compressive strength of joints are analyzed by square-inventory method in three areas with well-preserved outcrops. The study area is located in Ogcheon folded bet, and are composed of quartz-schist and quartzite in the Midongsan Formation and phyllite in the Ungyori Formation. Flexural beds by folding, schistosity and cleavage besides joints are developed due to slight metamorphism. Various types of joints developed by folding are formed such as strike-parallel, strike-perpendicular, wedge and wrench joint sets by both initially regional and later superposed folding. Factors of slope instability are created by crossing the orientations of joint, cleavage, bedding and slope one another. In the case that the orientation of a slope is coincident with one of beds, factors causing large-scale failure including plane failure are increased greatly. Also in the region that orientations of the slope and bed are crossed each other at high angle, only local and minor failures are shown in the slope.

• The Journal of Engineering Geology
• /
• v.27 no.2
• /
• pp.125-132
• /
• 2017

Approximately 64 percent of Korean territory is covered with mountains, and there is occurred a continuous mountain disaster such as landslide, debris flow and slope failure around mountain slopes due to heavy rainfall and typhoon in the summer season. Even in such a reality, the development of mountain areas is being carried out through the development and expansion of social infrastructures centered on mountain areas, but systematic management is insufficient. Constructions of a forest road facility for mountain slopes can be a cause of mountain disasters intensively in the summer season due to artificially changing the mountain area. In this unstable mountain environment, efforts to build a disaster-resistant environment are urgently needed. This research is to analyze the stability of mountain slopes according to soil depth (1~5 m) and mountain slope ($20{\sim}60^{\circ}$) considering the characteristics of rainfall infiltration under extreme rainfall conditions. As a result, the stability of the mountain slope was found to be different according to the depth of soils and the saturation area of the soil layer. As well as the stability of the mountain area was found to be lower than that of the natural mountain area. Specially, rainfall infiltration occurs at the upper slope of the forest road. For this reason, the runoff phenomenon of rainfall infiltration water occurs clearly when the depth of soil layer is low.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.10 no.4
• /
• pp.187-192
• /
• 2007

Impact on cylindrical surface caused by plunging breaking waves is investigated experimentally. The breaking waves are generated in a wave flume by decreasing the wave maker frequencies linearly and focusing the generated wave components at one specific location. The breaking wave packets are based on constant wave steepness spectrum. Three inclination angles of cylinder are applied to examine the effect of contact angle between cylinder and front surface of breaking waves. Also, the effect of cylinder diameter on pressure distribution and its peak value is investigated by adopting three cylinders with different diameters. The longitudinal location of cylinder is slightly moved in eight different points to find out a probable maximum value of impact pressure. The pressures and total force on cylinder surface are measured by piezo-electric pressure sensors and 3-components load cell with 30kHz sampling rate. The variation of peak impact pressures and forces is analyzed in terms of cylinder diameter, inclination angle and location. Also, the pressure distribution on cylindrical surface is examined. The cylinder location and surface position are more important parameters that govern the magnitude and shape of peak pressures, while the cylinder diameter and inclined angle are relatively insignificant. In a certain conditions, the impact phenomenon becomes very unstable which results in a large variation of measured valves in repeated runs.