板書（黒板や白板）を用いた講義では，講師が記述や説明をするために板書の前を遮ることがある．このとき，遮られた板書内容が見えず，ノートに書き写しにくいと感じる経験は多くある．我々の提案するシステムでは，カメラで撮影した板書映像を処理し，板書の前を遮る講師をシルエットにして透過することで，遮られた板書内容と講師の動きの両者が読み取れる映像を提供できる．我々の方法の特徴は，この映像処理をリアルタイムに実現することと，映像を講義室内のサブモニタで表示することによって板書遮蔽問題を解決することである．遮られた板書内容を提示する方法として，本手法のシルエットを透過表示する方法や講師を完全に消去する方法が考えられる．我々は提示方法として，どの方法が好まれるか比較実験をおこない，シルエットを透過して表示する方法が好まれるという結果を有意に確認した．

液体クロマトグラフィー/タンデム型質量分析法（LC/MS/MS）による水道水中のテフリルトリオン分析法の検討を行った．検討の結果，テフリルトリオンの検量線は0.2～0.02μg/L の濃度範囲で良好な直線性が得られた．また，0.02μg/L テフリルトリオン標準液の併行精度は1.2％であった．さらに，水道水の添加回収試験（n＝5，5日間）を実施し，妥当性を評価した結果，併行精度1.8％，室内精度3.5％，真度104％ともに良好な結果が得られた．

In this paper, we discuss the possibility of video streaming simply recorded “chalk and talk” lectures as review materials via LMS. We have recorded chalk and talk lectures in a course conducted by the first author and streamed them as review materials over the Internet via the LMS of our university for several years. On reviewing the view history of the videos, we found that more than 10％ of the students accessed the videos of the course, as the LMS became widely used among the students, and even some of the students accessed every single video. Therefore, in this study, we investigated how often students watched the lecture videos of the course. We also surveyed student evaluations of it, their purpose for watching the lecture videos, and how they watched them. We found that most of the students browsed parts of the lectures of which they felt they had some difficulty in understanding or where they wanted to learn more. Finally, we confirmed the possibility of video streaming lectures via LMS, as review materials, even if they were simply recorded videos of conducted lectures.

Although there are various lecture recording systems, they still have many problems. For instance, the type of lecture material which can be recorded is limited to PowerPoint Slides and recording process needs subsequent editing work. We developed a system which overcomes such limitation. The features of this system are threefold: 1) installation of software into instructor’s PC is unnecessary, 2) subsequent editing work is also unnecessary, and 3) high definition recording is possible. The system we developed allows creation of precise digital learning content.

We used our system for four years in actual university lectures. As a result of comparative analysis on its educational effect, the validity of the system can be proven. Two companies developed the products using the result of this research.