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        검색결과 1,092

        381.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper, we present a multi-period 0-1 knapsack problem which has the cardinality constraints. Theoretically, the presented problem can be regarded as an extension of the multi-period 0-1 knapsack problem. In the multi-period 0-1 knapsack problem, there are n jobs to be performed during m periods. Each job has the execution time and its completion gives profit. All the n jobs are partitioned into m periods, and the jobs belong to i-th period may be performed not later than in the i-th period, i = 1, ⋯, m. The total production time for periods from 1 to i is given by bi for each i = 1, ⋯, m, and the objective is to maximize the total profit. In the extended problem, we can select a specified number of jobs from each of periods associated with the corresponding cardinality constraints. As the extended problem is NP-hard, the branch and bound method is preferable to solve it, and therefore it is important to have efficient procedures for solving its linear programming relaxed problem. So we intensively explore the LP relaxed problem and suggest a polynomial time algorithm. We first decompose the LP relaxed problem into m subproblems associated with each cardinality constraints. Then we identify some new properties based on the parametric analysis. Finally by exploiting the special structure of the LP relaxed problem, we develop an efficient algorithm for the LP relaxed problem. The developed algorithm has a worst case computational complexity of order max[O(n2log n), O(mn2)], where m is the number of periods and n is the total number of jobs. We illustrate a numerical example.
        4,000원
        382.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This research investigated changes in Joseon food culture mainly focusing on acceptance of Western food in the enlightenment period. Joseon intended to learn the advanced technology of the West. Through an exchange with various Western countries, the royal family and upper class of Joseon rapidly accepted foreign food and food culture. As hotels were built in Incheon and Seoul, foreign food became more widely provided, which spread to the public, accordingly, and Western style restaurants were built and spread to the Busan area besides Seoul. As Western food rapidly spread, concerns arose. Particularly, after an attempt to assassinate Gojong by inserting poison into his coffee in 1898, appeals were made concerning Western food “that should not be consumed, because it is not proper for Korean people's intestines and stomach”.
        4,300원
        383.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Large spatial structures can not easily predict the dynamic behavior due to the lack of construction and design practices. The spatial structures are generally analyzed through the numerical simulation and experimental test in order to investigate the seismic response of large spatial structures. In the case of analysis for seismic response of large spatial structure, the many studies by the numerical analysis was carried out, researches by the shaking table test are very rare. In this study, a shaking table test of a small-scale arch structure was conducted and the dynamic characteristics of arch structure are analyzed. And the dynamic characteristics of arch structures are investigated according to the various column cross-section and length. It is found that the natural vibration periods of the small-scaled arch structure that have large column stiffness are very similar to the natural vibration period of the non-column arch structure. And in case of arch structure with large column stiffness, primary natural frequency period by numerical analysis is very similar to the primary natural frequency period of by shaking table test. These are because the dynamic characteristics of the roof structure are affected by the column stiffness of the spatial structure.
        4,000원
        386.
        2015.11 구독 인증기관·개인회원 무료
        국내 다수의 정수장이 적용하고 있는 전통적인 정수처리 공정만으로는 신규 유해물질이나 미량유해물질의 처리 보증을 할 수 없다. 안정적인 고도정수처리공정으로 막분리공정의 적용과 연구가 진행되고 있다. 원수의 특성에 따른 막여과 고도정수처리공정의 개발과 이에 대한 장기적인 검증이 필요하다. 본 연구에서는 계절에 따라 고농도의 망간이 발현되고 있는 경북 U정수장 내의 막여과 시설을 운영하면서 고도정수처리공정의 개발과 장기 성능 평가를 진행하였다. 막여과시설의 일처리용량은 1,000 m³으로 최적 운영인자 확보와 정수처리성능을 평가하였다.
        387.
        2015.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, shaking table test has been carried out for the dual frame passive control system for seismic performance verification of the proposed system. The proposed system was separated into two independent frameworks that are strength resistant core and frame structure by connecting to the damper. Moreover, the seismic performance improvement of the proposed system has been verified by comparing and analyzing the experimental results of the proposed system with an existing core system. As a result of the shaking table test, acceleration and displacement responses of dual-frame vibration control system are decreased than those of the existing strength resistant type core system. In the case of the core system, while the damage was concentrated on the column of first floor, the damage of the dual system was dispersed in each layer. The damage also was concentrated on the damper, almost no damage occurs to the structural members. It has been emphasized that installed dampers in the proposed dual system reduce the input energy of whole structure by absorbing seismic input energy, which leads overall system damage to be reduced.
        4,000원
        389.
        2015.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        동궁과 월지는 통일신라시대에 조성된 넓은 수면의 원지를 중심으로 한 궁원으로 추정된다. 원지는 입수부, 연못, 출수 부로 구성되어 있으며, 특히 입수부는 독자적인 특징을 보이는 수경시설로 구성되어 있다. 본 연구는 월지 입수부의 수경에 대한 디자인수법을 밝힘으로써 통일신라시대의 궁원을 이해하고 원지조영에 대한 작법의 단초를 제공하고자 한다. 연구방법으로 동궁과 월지에 대한 발굴조사 성과를 바탕으로 발굴조사의 내용과 복원된 수경시설에 대한 조사와 분석 을 통하여 입수부에 대한 수경 디자인수법을 도출한다. 원지의 입수부는 직선형수로, 석조, 소지, 계류형수로, 폭포로 구성되어 다채로운 수경을 연출하고 있는데 각각의 디 자인 수법은 다음과 같다. 기하학적인 인공형태의 직선형수로는 수로의 초입부에서 직각으로 수류방향을 바꾸는 굴절점 을 세 차례 반복하는 선형을 보이는데 이는 건축물의 축선을 따른 것으로 건축물의 세력권에 영향을 받은 형태의 디자인 수법으로 볼 수 있다. 상하로 연결된 2단 석조는 물을 담은 큰 그릇으로써의 이용을 고려한 것으로 상하의 단차에 의한 물의 약동은 시각 및 청각적인 효과를 위한 디자인수법이다. 또한 석조 주위의 판석과 외연벽석으로 형성된 한정된 공간 은 가장 가까이에서 물을 접할 수 있는 친수공간으로 디자인된 수경공간이다. 완만한 곡선의 타원형에 가까운 형태의 소지는 호안의 축조와 바닥처리 및 경석의 배치에 있어서 독자적인 디자인 수법을 보이며, 기능적으로는 폭포수의 일정 한 수량공급을 위한 저수지의 역할을 한다. 자연스러운 분위기를 연출하는 계류형 수로는 직선형 수로와 대비되는 디자 인으로 호안을 축조하는 방식에서 최대한 자연스럽게 보이기 위한 수법을 보여준다. 입수부의 마지막 단계로서 극단적 인 시각적 변화를 보여주는 폭포는 수로와 원지의 단차를 해결하는 디자인수법으로 사용되었으며, 위치설정에 있어서 완전노출을 피하여 흥미를 유발시키는 고차원의 수법이 적용되었다. 다섯 단계로 구성된 다채로운 입수부의 수경시설은 근접한 건축물의 영향을 받는 직선형의 인공적 디자인의 수경수법 에서 시작하여 점차적으로 그 영향에서 벗어나 자연스러움을 보여주는 디자인의 발전단계를 보여주는 수경시설의 디자 인수법을 보여주고 있다.
        4,300원
        390.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        LMC X-4 is an eclipsing high-mass X-ray binary exhibiting a superorbital modulation with a period of ~ 30.5 days. We present a detailed study of the variations of the superorbital modulation period with a time baseline of ~ 18 years. The period determined in the light curve collected by the Monitor of All-sky X-ray Image (MAXI) significantly deviates from that observed by the All Sky Monitor (ASM) onboard the Rossi X-ray Timing Explorer (RXTE). Using the data collected by RXTE/ASM, MAXI, and the Burst Alert Telescope (BAT) onboard Swift, we found a significant period derivative, _P = (2.08±0.12) X 10-5. Furthermore, the O{C residual shows complex short-term variations indicating that the superorbital modulation of LMC X-4 exhibits complicated unstable behaviors. In addition, we used archive data collected by the Proportional Counter Array (PCA) on RXTE to estimate the orbital and spin parameters. The detected pulse frequencies obtained in small time segments were fitted with a circular orbital Doppler shift model. In addition to orbital parameters and spin frequency for each observation, we found a spin frequency derivative of v = (6.482 ± 0.011) X 10-13 Hz · s-1. More precise orbital and spin parameters will be evaluated by the pulse arrival time delay technique in the future.
        3,000원
        391.
        2015.09 KCI 등재 구독 인증기관·개인회원 무료
        4U 1323-62, a low mass X-ray binary with an orbital period of 2.94 hr, exhibits periodic X-ray dips, which are due to absorption by the bulge of the outer accretion disk. The purpose of this study is to search for orbital period changes using archived X-ray data over a time span of 20 years. We present our preliminary results from analyzing light curves observed by RXTE, BeppoSAX, XMM-Newton and Suzaku. We used the method proposed by Hu et al. (2008) to estimate dip center time and adopted the Observed - Calculated method to measure changes in period. We obtained an orbital period of 2.941917(36) hr and a period derivative of _Porb=Porb = (-9.9 ± 3.5) X 10-7yr-1. The F-test result shows that the quadratic ephemeris is describes the evolution of the dip phases better than the linear ephemeris at a greater than 95% confidence level. More X-ray data collected from the early 80s will be included to further rfine the orbital ephemeris.
        392.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Classical Cepheids (hereafter Cepheids) belong to a class of important variable stars that can be used to determine distances to nearby galaxies via the famous period-luminosity (PL) relations, i.e. the Leavitt Law. In turn, these distances can then be used to calibrate a host of secondary distance indicators located well within the Hubble flow, and ultimately determine the Hubble constant in a manner independent of the Cosmic Microwave Background (CMB) measurements. Some recent progress in determining the Hubble constant to within ~ 3% level via the Cepheid-based distance scale ladder (the SH0ES and the Carnegie Hubble Program) were first summarized in this Proceeding, followed by a brief discussion on the prospect of using ultra-long period Cepheids (ULPC) in future distance scale work. ULPC are those Cepheids with periods longer than 80 days, which seem to follow a different PL relation than their shorter period Cepheids. It has been suggested that ULPC can be used to determine the Hubble constant in "one-step". However, based on the two ULPCs found in M31, it was found that the large dispersion in derived distance moduli leads to a less accurate distance modulus to M31 compared to the classical Cepheids. This finding might raise an alert regarding the use of ULPCs in future distance scale work.
        3,000원
        393.
        2015.09 KCI 등재 구독 인증기관·개인회원 무료
        One of the long-standing problems in modern astronomy is the curious division of globular clusters (GCs) into two groups, according to the mean period (hPabi) of type ab RR Lyrae variables. In light of the recent discovery of multiple populations in GCs, we suggest a new model explaining the origin of the Sandage period-shift and the difference in mean period of type ab RR Lyrae variables between the two Oosterhoff groups. In our models, the instability strip in the metal-poor group II clusters, such as M15, is populated by second generation stars (G2) with enhanced helium and CNO abundances, while the RR Lyraes in the relatively metal-rich group I clusters like M3 are mostly produced by first generation stars (G1) without these enhancements. This population shift within the instability strip with metallicity can create the observed period-shift between the two groups, since both helium and CNO abundances play a role in increasing the period of RR Lyrae variables. The presence of more metal-rich clusters having Oosterhoff-intermediate characteristics, such as NGC 1851, as well as of most metal-rich clusters having RR Lyraes with the longest periods (group III) can also be reproduced, as more helium-rich third and later generations of stars (G3) penetrate into the instability strip with further increase in metallicity. Therefore, although there are systems where the suggested population shift cannot be a viable explanation, for the most general cases, our models predict that RR Lyraes are produced mostly by G1, G2, and G3, respectively, for the Oosterhoff groups I, II, and III.
        394.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We review recent results on superhump period variations in SU UMa-type dwarf novae. Our statistical studies have revealed that the evolution of the superhump period is basically composed of three stages: stage-A, during which the superhump period is long and constant, stage-B, during which the superhump period increases as the superoutburst proceeds, and stage-C, during which the superhump period is short and constant. We also introduce a new method of estimating a mass ratio using the stage-A superhump period. This method can extend to, for example, low mass X-ray binaries or AM CVn stars if the stage-A superhump period is well determined.
        3,000원
        395.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We investigated the period variation for 79 eclipsing binary systems using 20 years (1990-2009) of EROS, Macho, and OGLE survey observations. We discovered 9 apsidal motions, 8 mass transfers, 5 period increasing and decreasing systems, 12 light-travel-time effects, 5 eccentric systems and 40 other systems showing no period variations. We select 3 representative eclipsing binary systems; EROS 1052 for apsidal motion, EROS 1056 for mass transfer, and EROS 1037 for the light-travel-time effect. We determine the period variation rate (dP/dt), orbital parameters of the 3rd body (e3, ω3, f(m3), P3, T3), apsidal motion parameters (dω/dt, U, Ps, Pa, e) and apsidal motion period by analyzing the light curves and O-C diagrams.
        3,000원
        396.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We use ALLWISE data release W1- and W2-band epoch photometry collected by the Wide-Field Infrared Survey Explorer (WISE) to determine slopes of the period-luminosity relations for RR Lyrae stars in 15 globular clusters in the corresponding bands. We further combine these results with V- and K-band photometry of Galactic field RR Lyrae stars to determine the metallicity slopes of the log PF - [Fe/H]-MK, log PF - [Fe/H]-MW1, and log PF - [Fe/H]- MW2 period-metallicity-luminosity relations. We infer the zero points of these relations and determine the kinematical parameters of thick-disk and halo RR Lyraes via statistical parallax, and estimate the RR Lyrae-based distances to 18 Local-Group galaxies including the center of the Milky Way.
        4,000원
        397.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        근권부 공기순환 덕트 냉방이 온도 및 생육에 미치는 영향을 구명하고자 고온기 파프리카((Capsicumannum.L. ‘Veyron’)을 코이어배지에서 수경재배하였다. 냉방시간 처리는 24시간 연속 가동한 연속냉방(All-day), 17시부터 다음날 1시까지 8시간 냉방한 야간냉방(Night), 대조구인 냉방 무처리(Control) 등 3 처리하여 온실 상·하부 온도, 근권온도, 엽온, 과실 특성 및 기관 분배율을 측정하였 다. 근권부 덕트 냉방하였을 때, 고온기(6월 ~8월) 온실 하부(바닥으로부터 40cm)와 상부(바닥으로부터 180cm) 온도, 근권온도는 하강되었다. 대조구와 비교하여 온실 하부/상부 온도 차이가 연속냉방에서는 4.4~5.1oC/ 2.1~3.1oC 하강을, 야간냉방 처리에서는 3.4~3.8oC/ 2.2~2.7oC 하강되었다. 근권온도는 온실 하부 온도 결과와 유사했으며, 연속냉방(22.8oC)> 야간 냉방(24.1oC) > 대조구(27.7oC) 순으로 온도가 낮았다. 연속냉방 처리에서 덕트 위치(통로, 베드하단)와 송풍 방향(45o, 90o, 180o)에 따른 온도 변화를 측정한 결과 덕트의 위치가 통로에 위치하고 송풍방향이 상향(45o) 또는 수평(180o) 인 처리는 지상부 100cm까지의 수직 위치에 따른 온도 차이가 크지 않지 않으면서, 근권부위 온도인 지상 50cm 온도가 낮은 특징을 보였고 베드와 베드 공간 사이로 덕트 송풍 방향이 직각(90o)이였을 때는 바닥과 지 상 50cm 부위의 온도가 높고, 지상 100cm 이상 200cm 부위 온도가 상대적으로 낮았다. 연속냉방 또는 야간냉방 처리했을 때 파프리카 엽온은 오후 7시가 오전 9시 보다 엽온 하강이 컸다. 과실 분배율은 대조구(24.4%)에 비해 연속냉방(48.6%)과 야간냉방(45.6%)에서 높았으며, 평균과중, 과수 및 수량도 연속냉방 처리에서 가장 높았다. 한편 야간냉방 처리에서도 고온기 평균 지상부 및 근권온도를 낮추었으나, 누적된 평균온도가 가장 낮은 연속냉방처리에서 과실로의 동화산물 분배율을 높여 파프리카 수량을 증가시킨 것으로 보인다.
        4,000원
        398.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The study was conducted to investigate the effects of post-incubation period and temperature treatment conditionsduring incubation on the uniform primordia formation and cultural characteristics of oyster mushroom (Pleurotus ostreatus). Threekinds post-incubation period; 25, 30, 35 days and control were applied for 30 days while two kinds incubation roomtemperature 23oC and 26oC and control were used 20oC. The substrate temperature during pre-incubation was of ‘Suhan No. 1’and ‘Gonji No. 7’. Oyster mushroom varieties tended to increase between 24oC to 26oC at 11 to 15 days after inoculation andthen they were maintained in treatment temperature during post -incubation period. The CO2 occurrence was at the highest at6,500ppm for ‘Suhan No. 1’ and 5,800ppm for ‘Gonji No. 7’ at the time of the highest temperature increase. The ratio of un-uniformal primordia formation and the ratio of non-commercial fruit body were reduced by 40%, 10.5%, respectively comparedto control for ‘Suhan No. 1’ when in the post-incubation temperature was 26oC, and incubated for 10days and 15daystreatment. Also, ‘Gonji No. 7’ was reduced by 19%, 9.5%, respectively when in the post-incubation temperature was 26oC, andincubated for 10 days treatment. Therefore, the higher post-incubation temperature of room and longer post-incubation periodresulted in the higher percentage of primordia formation of two cultivars.
        4,000원
        399.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        복숭아씨살이좀벌(Eurytoma maslovskii)에 의한 전남지역 매실 낙과피해는 해안지역인 완도, 신안, 여수, 무안을 제외한 전 지역에 발생하였고 평균 피해과율은 2013년 67%, 2014년 33.3%였다. 이 씨살이좀벌은 매실 씨방에서 노숙유충으로 월동을 하는데 7, 8월의 장마철을 지나며 생존율이 30% 내외가 되었다. 알은 길이 0.68 mm, 폭 0.29 mm의 유백색이며 장타원형으로 양 끝부분에 실모양의 돌기를 붙이고 있다. 다 자란 노숙유충은 길이 6.56 mm, 폭 3.18 mm이다. 번데기는 검정색 나용이고, 성충은 암 6.97 mm, 수 4.90 mm이고 암컷의 산란관 길이는 0.64 mm였다. 성충 우화시기는 4월 상순(매실 직경 4 mm)~5월 상순(17 mm)이고, 우화 최성기는 4월 중순이었다. 성충의 평균수명은 13.5일이고, 암수 성비는 45.9 : 54.1이다. 과일당 평균 산란수는 1개 61.5%, 2개 30.8%이고 최대 4개까지 산란하였지만 동종포식에 의해 최종적으로 1마리의 유충만 서식한다. 성충의 매실에 산란시기는 4월 하순(직경 12~16 mm)이며 그 후에는 씨방벽이 딱딱하게 경화되어 유충이 씨방으로 침투가 어려워진다. 따라서 성충의 산란을 예방하기 위한 방제적기는 4월 중순부터 5일 간격으로 2~3회 적용약제를 살포하는 것이다.
        4,000원
        400.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we hypothesized that the size of wintering crane population would change due to the climate factors. We assumed that wintering population size would differ by climate values in January, which is the coldest period in year. Especially, White-naped cranes were able to choose wintering site between Cheorwon and other alternative place where snow coverage had low influence, differing from Red crowned cranes. For this reason, we predicted the population size of White-naped cranes would fluctuate according to the extent of snow coverage in Cheorwon. Therefore we used snow coverage data based on MODIS and climate data from KMA (Korea Meteorological Administration) that are generally used. We analyzed the crane’s population size in Cheorwon in January from 2002 to 2014. The temperature in the Cheorwon increased from 2002 to wintering period in 2007~ 2008 and went down, showing the lowest temperature in 2011~ 2012. With this phenomenon, warmth index showed the similar pattern with temperature. Amount of newly accumulated snow (the amount of snow that fallen from 0:01 am to 11:29 pm in a day) was low after 2002, but rapidly increased in 2010~ 2011 and 2011~ 2012. The area of snow coverage rapidly declined from 2002 to 2005~ 2006 but suddenly expanded in wintering period in 2009~ 2010 and 2010~ 2011. Wintering population size of the White-naped cranes decreased as snow coverage area increased in January and the highest correlation was found between them, compared to the other climatic factors. However, the number of individuals of Red crowned cranes had little relationship with general climate factors including snow cover range. Therefore it seems that population size of the Red crowned crane varied by factors related with habitat selection such as secure roosting site and area of foraging place, not by climatic factors. In multiple regression analysis, wintering population of White-naped cranes showed significant relationship with logarithmic value of snow cover range and its period. Therefore, it suggests that the population size of the White-naped crane was affected by snow cover range n wintering period and this was because it was hard for them to find out rice grains which are their main food items, buried in snow cover. The population size variation in White-naped cranes was caused by some individuals which left Cheorwon for Izumi where snow cover had little influence on them. The wintering population in Izumi and Cheorwon had negative correlation, implying they were mutually related.
        4,300원