웹을 활용한 초등학교 과학과 수행평가 측정 도구의 개발

최문수,정인기 춘천교육대학교 과학교육연구소 2002 과학교육연구 Vol.26 No.-

온라인 서점 선택의 영향 요인 연구

이미경,최문기,노재정 한국인터넷비즈니스학회 2001 인터넷비지니스연구 Vol.2 No.1

본 연구는 온라인 쇼핑몰 확산 과정에서 소비자에게 인지된 가격 할인 혜택과 인터넷의 강점인 정보 탐색의 용이성, 고객 개개인에 대한 개인화 서비스 등이 실제 소비자들의 온라인 사이트 방문과 구매에 미치는 영향을 선행 연구들로부터 도출하고, 이들 영향이 국내 온라인 도서 소비자의 방문 및 구매 선호와 어떻게 관련되는지를 조사하며, 그 결과로 온라인 서점의 수익 개선에 필요한 시사점을 도출하려는데 목적을 두고 수행되었다. 연구결과 정보제공과 개인화 추천 서비스의 두 가지 요인이 도서 구매 고객의 방문 선호에 영향을 미치는 변수였으며, 구매 선호에 영향을 미치는 변수로는 정보제공과 가격할인의 두 가지 요인이었다. 또한, 방문 선호는 구매 선호에 유의한 영향을 주었다. 이러한 연구결과를 통해 소비자의 인터넷 사용 경험이 쌓여감에 따라 온라인 서점의 경쟁우위는 가격보다는 정보의 중요성쪽으로 옮겨가고 있음을 확인하였다. The literature survey of online bookstores shows that consumer's visits to online bookstores and his/her purchasing decision to the sites are strongly related to three factors, price discounts, easy gathering of book information and personalized services. This paper surveys and analyzes how these factors affect consumer's visits and his/her purchasing decision in Korean online book market in order to improve the revenue of online bookstores. The results show that the selection of visiting online bookstores are mainly affected by the provision of book information and personalized services, and consumer's choice of purchasing sites are affected by the price discounts and the provision of book information, It is also shown that the consumer's choice for purchasing at a specific site are highly dependent on the selection of visiting online bookstores.

능동표적신호합성 알고리듬의 실시간 구현

김희성,김우식,최상문,한동훈,신기철,김재수 韓國海洋大學校 附設 海洋科學技術硏究所 1997 硏究論文集 Vol.6 No.-

The simulation of target-scattered echo with the moving sonar platform and target in 3-dimensional ocean environment is essential to validate and evaluate the performance of a sonar system. This paper presents the improved target signal simulation on the basis of the highlight(HL) model and its realtime algorithm. In order to simulate the scattering highlight, the highlight is represented as a directional scatterer. The realtime generation algorithm of the target signal is realized by use of DSP chip, TMS320C40, where the 40 channels are equally separated to form a parallel processing task in 4 processors. The presented realtime-version of target signal simulation can be used as a target signal simulator in the development of ACM(Acoustic Counter Measure) and advanced sonar signal processing techniques.

ETRI (한국전자통신연구원)

최문기(Choi Mun-Kee) 한국자동차공학회 2008 오토저널 Vol.30 No.6

77K에서 SC(NH₂)₂의 ¹⁴N 핵사중극 공명연구

최숙자,박영민,박현진,전인,송승기,서용문 명지대학교 자연과학연구소 1997 자연과학논문집 Vol.16 No.-

강유전체 질소화합물 thiourea [SC(NH₂)₂]분말시료의 ??plused NQR 실험을 77K 에서 실행하여 공명진동수와 핵사중극 결합상수, 비대칭인자, 완화시간등을 측정했으며, 4개의 공명선이 관측되었다. 결정내에는 주위 환경이 다른 두 종류의 질소 N₁,N₂가 존재함을 알 수 있었다. N₁에 관한 공명진동수는 ??(1)=2.6487㎒, ??(1)=2.032㎒, N₂에 대하여는 ??(2)=3.1852㎑, ??(2)=2.0183㎒이고, 공명선폭은 ??(1)=2.6752㎑, ??(1)=3.1852㎑, ??(2)=3.2618㎑, ??(2)=3.5448㎑ 임을 보였다. 한편 e²qQ/h의 값은 ν(1)에서 3.1205㎒, η는 0.3953이었으며, ν(2)에서는 3.0279㎒, 0.3939이었다. 이는 이미 보고된 결과와 일치하였다. 그리고, FID(Free Induction Decay)와 spin-echo실험을 통하여 얻은 스핀-격자 완화시간 T₁은 ??(1)에서 7.143 s, ??(2)에서 5.88 s이었으며, 스핀-스핀 완화시간 T₂는 ??(1)에서 25㎳, ??(2)에서 33.3㎳, ??(2)에서 33.3㎳의 값을 얻었다. We have measured ??N NQR frequencies, nuclear quadroupole coupling constants, asymmetric parameters and relaxation times in ferroelectric nitrogen thiourea [SC(NH2)2] at 77K, and four NQR resonance lines were observed. The results of measurements show that there are two kinds of nitrogen site, N1 and N2, with different environments in the crystal. The resonance frequencies were found to be ν+(l)=2.64 87MHz, ν_(1)=2.032 MHz for N1 and ν+(2)=2.6285MHz, ν_(2) =2.0183MHz for N2 respectively. The corresponding linewidths were ν+(1)= 2.6752kHz, Δν_(l) =3.1852kHz, ν+(2) =3.2618kHz and Δν_(2) =3.5448kHz, respectively. For N1, e2Q/h is 3.1205 MHz and η is 0.3953, and for N2, these are 3.0979MHz and 0.3939. These results are in agreement with those reported previously. The spin-lattice relaxation time (Ti) and the spin-spin relaxation time (T2) by FID and spin-echo experiments are as follows : T1(ν+(1)) is 7.143 s and T1(ν+(2)) is 5.88 s. T2(ν+(1)) is 25 ms, T2(ν_(1)) is 25 ms, T2(ν+(2)) is 33.3 ms and T2(ν_(2)) is 33.3 ms.

Axin1 expression facilitates cell death induced by aurora kinase inhibition through PARP activation

Choi, Eun‐,Jin,Kim, Shi‐,Mun,Song, Ki‐,Joon,Lee, Jae‐,Myun,Kee, Sun‐,Ho Wiley Subscription Services, Inc., A Wiley Company 2011 Journal of cellular biochemistry Vol.112 No.9

<P><B>Abstract</B></P><P>Axin, a negative regulator of Wnt signaling, participates in apoptosis, and Axin1 localizes to centrosomes and mitotic spindles, which requires Aurora kinase activity. In this study, Aurora inhibition of Axin1‐expressing cells (L‐Axin) produced polyploid cells, which died within 48 h posttreatment, whereas Axin2‐expressing cells (L‐Axin2) survived the same period. These cell death events showed apoptotic signs, such as chromatin condensation and increased sub‐G1 populations, as well as cell membrane rupture. Further analysis showed that Aurora kinase inhibitor (AKI) treatment of L‐Axin cells induced poly(ADP‐ribose) polymerase (PARP) activation, which increased the poly(ADP‐ribosyl)ation of cellular proteins and reduced cellular ATP content. PARP inhibition reduced a proportion of dead cells, suggesting PARP involvement in AKI‐induced cell death. Also, AKI treatment of L‐Axin cells induced mitochondrial apoptosis‐inducing factor (AIF) release, but not mitochondrial cytochrome <I>c</I> release or caspase‐3 activation. Knockdown of AIF attenuated AKI‐induced cell death in L‐Axin cells. Thus, our results suggest that Axin1 expression renders L929 cells sensitive to Aurora inhibition‐induced cell death in a PARP‐ and AIF‐dependent manner. J. Cell. Biochem. 112: 2392–2402, 2011. © 2011 Wiley‐Liss, Inc.</P>

Correction with blood T1 is essential when measuring post-contrast myocardial T1 value in patients with acute myocardial infarction

Choi, Eui-Young,Hwang, Sung Ho,Yoon, Young Won,Park, Chul Hwan,Paek, Mun Young,Greiser, Andreas,Chung, Hyemoon,Yoon, Ji-Hyun,Kim, Jong-Youn,Min, Pil-Ki,Lee, Byoung Kwon,Hong, Bum-Kee,Rim, Se-Joong,Kwo BioMed Central 2013 Journal of cardiovascular magnetic resonance Vol.15 No.-

<P><B>Background</B></P><P>Post-contrast T1 mapping by modified Look-Locker inversion recovery (MOLLI) sequence has been introduced as a promising means to assess an expansion of the extra-cellular space. However, T1 value in the myocardium can be affected by scanning time after bolus contrast injection. In this study, we investigated the changes of the T1 values according to multiple slicing over scanning time at 15 minutes after contrast injection and usefulness of blood T1 correction.</P><P><B>Methods</B></P><P>Eighteen reperfused acute myocardial infarction (AMI) patients, 13 cardiomyopathy patients and 8 healthy volunteers underwent cardiovascular magnetic resonance with 15 minute-post contrast MOLLI to generate T1 maps. In 10 cardiomyopathy cases, pre- and post-contrast MOLLI techniques were performed to generate extracellular volume fraction (Ve). Six slices of T1 maps according to the left ventricular (LV) short axis, from apex to base, were consecutively obtained. Each T1 value was measured in the whole myocardium, infarcted myocardium, non-infarcted myocardium and LV blood cavity.</P><P><B>Results</B></P><P>The mean T1 value of infarcted myocardium was significantly lower than that of non-infarcted myocardium (425.4±68.1 ms vs. 540.5±88.0 ms, respectively, p< 0.001). T1 values of non-infarcted myocardium increased significantly from apex to base (from 523.1±99.5 ms to 561.1±81.1 ms, p=0.001), and were accompanied by a similar increase in blood T1 value in LV cavity (from 442.1±120.7 ms to 456.8±97.5 ms, p<0.001) over time. This phenomenon was applied to both left anterior descending (LAD) territory (from 545.1±74.5 ms to 575.7±84.0 ms, p<0.001) and non-LAD territory AMI cases (from 501.2±124.5 ms to 549.5±81.3 ms, p<0.001). It was similarly applied to cardiomyopathy patients and healthy volunteers. After the myocardial T1 values, however, were adjusted by the blood T1 values, they were consistent throughout the slices from apex to base (from 1.17±0.18 to 1.25±0.13, p>0.05). The Ve did not show significant differences from apical to basal slices.</P><P><B>Conclusion</B></P><P>Post-contrast myocardial T1 corrected by blood T1 or Ve, provide more stable measurement of degree of fibrosis in non-infarcted myocardium in short- axis multiple slicing.</P>

슬관절 전치환술에서 측정한 한국인의 경골 근위부 절단면 분석에 대한 연구

최영준,김덕근,양문승,정현기,최충혁 대한슬관절학회 1997 대한슬관절학회지 Vol.9 No.1

In shape and dimensions, the tibial plateaus are asymmetric with the larger medial tibial plateau and both have a posterior inclination with respect to the shaft of the tibia. Maximizing tibial coverage is an impotant consideration in total knee arthroplasty to provide stability and load transfer and to improve long-term survival rate of the implants. Most tibial tray designs are symmetric, but several asymmetric designs are available. We evaluated the proximal tibial resection surface during total knee aithroplasty to delineate the tibial plateaus in korean. After tibial bone cut during 100 TKA procedures, the outline of tibial resection surface was traced and rotational axis of true tibial component was marked intraoperatively. A line was drawn at the maximal anteroposterior(AP) diameter of lateral tibial condyle with parallel to rotational axis of component, and then a transverse axis was drawn at the midpoint of maximal AP diameter of lateral tibial condyle. Anteroposterior 10, 20, 30, 40% and midpoint from the medial and lateral peripheries were calculated manually. The average AP medial 10, 20, 30 and 40% dimensions were 34.7, 43.8, 48.0 and 43.2mm, respectively. The average AP lateral 10, 20, 30 and 40% dimensions were 30.2, 38.4, 42.0 and 40.9mm, respectively. The ratio of medial/lateral AP dimensions 10, 20, 30 and 40% from periphery were 116.9, 114.7, 114.5 and 106.4%, respectively. From these data, we know the asymmetry of the proximal tibial plateaus in korean. We hope that more data will be ohtained in multicenter studies and it will help us to select tibial tray and to design the tibial component in korean. But, more accurate standard measures will be need to minimize an error of measurements.

Performance Benefits of Virtual Path Tunneling for Control and Management Flows in the Broadband ATM Network

Choi, Jun-Kyun,Kim, Soo-Hyung,Kim, Nam,Sohn, Sung-Won,Choi, Mun-Kee Electronics and Telecommunications Research Instit 1999 ETRI Journal Vol.21 No.4

In this paper, we analyze the performance benefits of broadband ATM networks when the call control and management flows are separated from user data flows. The virtual path tunneling concept for control and management flows are applied to the same physical ATM networks. The behaviors of channel throughput and transfer delay are analyzed. It results that the proposed virtual short-cut paths can maintain the network being stable with acceptable bandwidth. They are very useful to provide the stable control and management capabilities for Internet and mobile applications in the broadband ATM networks. In our numerical results, the effective throughputs of the proposed virtual shout-ut channel are about three times than those of end-to-end user data channels with hop distances of 10, and about two times than those with hop distance of 5 when the link blocking probability increases to 0.1. It concludes that the effective channel bandwidth are greatly reduced down while physical links are not stable and user traffic flows are occasionally overflowed.

Research Articles : Comparative Trapping Efficiency of Five Different Blends of the Two Sex Pheromone Components in Dichocrocis punctiferalis (Lepidoptera: Pyralidae) at Chestnut Orchards in Korea

( Choi Kwang Sik ),( Won Il Choi ),( Chong Kyu Kee ),( Young Jae Kim ),( Mun Jang Jeon ),( Sang Chul Shin ) 한국임학회 2008 한국산림과학회지 Vol.97 No.5