Analysis of Pattern Generalization Problems of Korean Mathematics Textbook

Lee,Chong Hee,Lee,Soo Youn 이화여자대학교 교과교육연구소 2013 교과교육학연구 Vol.17 No.4

The purpose of this study is to better understand the pattern generalization problems posed in the current school curricula of Korea. Twelve of most recently published elementary school (1st to 6th grade) mathematics textbooks and twelve Middle school (7th to 9th grade) mathematics textbooks (a total of 24 mathematic textbooks) were selected for the analysis. First, the different types and characteristics of pattern generalization problems based on previous research were categorized. Within these categories, we analyzed which pattern problems were emphasized in the school curriculum. The results indicate that ‘relating problems’ were mainly introduced in elementary school textbooks. ‘Searching for the same relationship’ and ‘procedure problems’ increased across the grades. ‘Pattern searching problems’ decreased across the grades, while ‘result searching’ and ‘pattern extension problems’ were rarely introduced. ‘Justification problems’ were inconsistently emphasized across the grades. With respect to the situational characteristics of the pattern generalization problems, ‘factual pattern generalization problems’ were consistently introduced across the grades, while ‘contextual pattern generalization problems’ and ‘symbolic pattern generalization problems’ were introduced only to a limited extent. Regarding the various types of pattern problems, only limited types of problems were proposed in both the elementary and middle school mathematic textbooks. From this study, we hope to address how the pattern generalization problems in the Korean mathematics curriculum lack pattern exercises in the curriculum core. We also hope to provide data which could lead to the development of a variety of pattern generalization problems in Korean mathematics textbooks in the future.

Theoretical Analysis and Performance Prediction of Axial-flow Rotary Separator

Kim, Chul Soo,Lee, Seung Kyu,Lee, Chong Ho 전북대학교 농업과학기술연구소 1985 農大論文集 Vol.16 No.-

脫穀作業은 全般的인 穀物生産 作業體系中에서 차지하는 比重이 크고 많은 勞動力을 必要로 하는 作業으로써 오늘날 先進國에서는 콤바인의 穀物 收護·脫穀作業에 널리 利用되고 있으며 그 利用率이 急激히 增加하고 있는 趨勢이다. 現在 利用되고 있는 콤바인의 穀粒 選烈方式은 重力과 貫性에 依存하는 straw-walker 方式을 採擇하고 있는 바 이는 콤바인의 容量을 制限하는 主要因이 되고 있으며 또한 過度한 穀粒損失의 原因이 된다. 따라서 重力依存度를 낮게함과 同時에 여러가지 種類의 作物狀態에도 安定性이 있는 選別機 開發의 必要性이 壇顧되고 있는 實情이다. Strow-walker 方式을 代替할 수 있는 選別機로는 選別作業에 遠心力을 利用하며 作物의 連續的인 移動을 可能하게 하는 軸流 回轉形 選別機를 들 수 있으며 이것은 憤行의 選別機에 比해 여러가지 長點이 있는 것으로 報告된 바 있다. 國內外의 많은 硏究가들에 依해 새로운 選別機 開發을 위한 여러가지 接近이 試圖되고 있는 바 理論的인 援近보다는 主로 實驗的이고 經驗的인 擺近을 通한 硏究가 盛行하고 있는 實情이다. 그러나 邏別戮內에서의 作物의 擧勳에 關與하는 因子들이 많기 때문에 實驗的인 援近方式으로는 作物擧勳에 關한 斷片的인 情報만을 얻을 수 있을 뿐이므로 作物의 擧勳을 槪括的으로 豫寮하기 爲하여서는 理論的인 擺近이 必要하게 된다. 따라서 本 硏究에서는 水平 圓錐形 軸流 回轉 選別機의 性能과 作物의 擧動을 理論的인 解析을 通하여 豫測하여 同 選別機의 設計要因을 分析하기 爲하여 遂行되었다. 본 硏究에서 分析된 選別機의 骨格은 크림프綱으로 된 圓錐形 選別綱과 그안에서 回轉 圓錐形 로우터로 되어 있으며 回轉로우터에는 作物에 回轉力을 주기 위한 級齒가 螺旋形으로 排列되어 있다. 本 硏究에서는 選別機 內에서의 作物의 移動에 關한 運動方程式과 짚으로부터 穀粒의 選別過程에 對한 方程式等이 誘導되었으며 컴퓨터 프로그램에 依하여 이 方程式들의 解를 求하였다. 이들 方程式의 解를 求하여 分析한 結果들은 供試된 圓錐形 選別機가 充分한 選別機能을 發揮할 수 있으며 圓錐角과 로우터의 回轉速度가 選別機內 作物滯留時間에 크게 影響을 미친다는 事實을 보여 주었다. 圓錐角이 20°以上인 境遇에는 回轉速度가 낮더라도 選別機內 作物滯留時間이 너무 짧아 選別機會가 줄어들기 때문에 圓錐角은 15°以內로 設計되어야 할 것으로 判斷되었다. 또한 選別效率을 向上시키기 爲해서는 作物의 軸方向速度를 制御할 수 있는 것을 選別綱 內部面에 附着하는 方法이 바람직할 것으로 思料되었다. 또한 選別綱을 로우터의 回轉方向과 같은 方向으로 回轉시켜 주면 選別效率을 높일 수 있으며 이 境遇 選別綱의 回轉速度가 로우터 回轉速度의 1/5程度일 때 選別效率이 가장 높은 것으로 나타났다. 아울러 分析된 圓錐形 選別機는 比較的 높은 濕度의 作物選別作業에도 適應性이 높을 것으로 思料되었다. The objective of this study was to predict, by theoretical analysis, performance of the horizontal conical separator which has been predetermined. A horizontal conical separator which was designed and tested experimentally by Lee13) was analyzed in this study. A theoretical analysis was made to derive the equation for the motion of the grain while in contact with the outer cone and the equation for the motion of the gain moving through the straw mat. Also, the equation of the probability of grain passage through the perforation of the sieve, which would be affected by the approaching angles of gain to the sieve, was developed. The computer was used to simulate the crop motion and a series of runs was made to obtain predicting information on the separation performance for the different values of system parameters such as cone half angle, angular rotor speed, cone entrance radius, blade pitch and sieve-to-rotor speed ratio. In each run, the crop motion was simulated for several values of one parameter while other parameters were held constant. Results from the computer simulation showed that the horizontal conical rotating separator was capable of subjecting the crop to the desired level of centrifugal acceleration, and that cone angle and angular rotor speed critically influenced crop dwell time within the separator. If the cone half angle were above 20 defee, the dwell time of the crop within the separator would be too short even at low rotor speed. The cone half angle, therefore, should be reduce to be1ow 15degree. Either attaching the helical blades to control the crop axial velocity or rotating the sieve in the same direction to the rotor would result the good separating efficiency. And the axial-flow separator was found to be suitable for the high moisture crops.

睡液中 Testosterone의 含量과 血淸中 High Density Lipoprotein Cholesterol의 消長이 座瘡發生에 미치는 效果

李容五,卞種秀 慶北大學校 齒科大學 1985 慶北齒大論文集 Vol.2 No.1

Sex hormone levels are possibly related to risk of heart disease through lipoprotein levels, specifically high density lipoprotein (HDL) cholesterol. HDL cholesterol is a powerful protective factor. Women have higher HDL cholesterol levels than men. Female sex hormones appear to be strongly related to HDL cholesterol; estrogen increases and progesterone decrease HDL cholesterol levels. There is some suggestion that pharmaceutical doses of testosterone will lower HDL cholesterol levels. Little is known about the relation between endogenous testosterone and HDL cholesterol levels. Acne is considered to be an androgen dependent condition and free testosterone in saliva is a useful marker of androgenicity in acne. Hence concentrations of salivary and serum testosterone, serum HDL cholesterol, total cholesterol, triglycerides and phospholipids were determined in male and female patients with varying grades of acne. Levels of salivary testosterone in male patients with acne cystica were slightly higher than those of men without acne, while men and women with acne vulgaris and women with acne cystica had normal salivary testosterone values. Levels of serum testosterone in male and female patients with acne (vulgaris or cystica) were not significantly different from those of controls. Levels of HDL cholesterol in male and female patients with acne cystica were significantly reduced as compared with levels in sex-matched controls and patients with acne vulgaris, while levels of total cholesterol, triglycerides and phospholipids in male and femal patients with acne (vulgaris or cystica) were not significnat. Salivary testosterone levels were negatively correlated with HDL cholesterol in male patients with acne, while salivary testosterone levels were positively correlated with HDL cholesterol in femal patients with acne.

Holography에 의한 Loudspeaker Cone의 振動에 관한 考察

李慶源,朴鍾允,林鍾洙,朴興秀 成均館大學校 科學技術硏究所 1984 論文集 Vol.35 No.1

Optical holographic interferometry is used to study the forced vibrational cone behaviour at some frequencies and photographs of resultant hologragm images are included. The entire cone vibrates almost uniformly in the low frequency region. Above certain frequency both transverse and longitudinal waves are coupled and together determine the vibration patterns. The coupling between longitudinal and bending waves gives rise to an antiresonance that the transverse amplitude become large. Bending waves only occur above the frequency at which this antiresonance occur. As the frequency increases, the resonance effect gradually progresses from the outer edge to the inner edge.

PID 制御器의 最適 自動 調整

鄭源鎔,金鳳載,李壽欽,朴賢泰 慶南大學校 附設 工業技術硏究所 1994 硏究論文集 Vol.12 No.-

In this paper, we propose a new method to deal with the optimal auto-tuning of the PID controller that is used to control process in various fields. First order delay system that was modeled from the unit step response of the system is Pade-approximated, and initial PID parameters are determined by the Ziegler-Nichols method. This method requires calculation of the weight function that includes the maximum overshoot, damping ratio, rising time and setting time by analyze the response of system. Finally, repeating these processes, we can find the parameters of PID controller so as to minimize the weight function. This method has a good adaptability even though variations in characteristics and dead time of the system.

天然洗劑의 生物分解에 관한 硏究

이춘식,최종수,박승조 동아대학교 환경문제연구소 1993 硏究報告 Vol.16 No.1

We were investigated with biodegradation of natural detergent by using jar-test, column test and activated sluge process. We were studied the BOD loading rate, the removal rate of organic material, the relationship between F/M, ratio, BOD and SS, SRT and MI, VSS/MLSS ratio. The results are summarized below. 1. In case of column height 160cm, suspended solid removal rate was 60.93%, COD, BOD and SS removal rate were 40%, 33% and 87% repectively in jar-test. In this case dosage of coagulant was 40.9g/㎥ alum, 4.5g lime/㎥ and 0.4g/㎥ polymer. 2. Wastewater containing natural detergent concentrationabout 600-1300mg/l was treated with activated sludge process and then removal rate of BOD is 80% in winter atmospheric temperature. In this case BOD concentration was about 10mg/l. 3. Wastewater containing natural detergent was treated with activated sludge process and then BOD volumetric loading rate is 0.3-0.8kg BOD/㎥·d. In this case BOD removal rate was about 90 %, MLVSS/MLSS ratio was 0.4-0.5 and SVI is 60-200.

SOI를 이용한 Back Side Trenched Asymmetric 1X2 Y-Branch Thermo-Optical Waveguide Switch

이기수,박종대 明知大學校 産業技術硏究所 2002 産業技術硏究所論文集 Vol.21 No.-

A Back Side Trenched asymmetric 1×2 Thermo-Optic Y-branch waveguide Switch based on SOI is proposed and farbricated. The proposed switch has a at the side of silicon substrate. The power consumption for SOI trench thermo-optic switch is 25% lower than that of SOI thermo-optic switch without trench. The crosstalk is as good as 21dB(TE) at the 1.55 ㎛ wa velength

大邱地域製造業體의 國際競爭力 强化方安

李種永,李秀珩,崔利圭 경북대학교 경제경영연구소 1992 經商論集 Vol.20 No.3

任婦 車事故 損傷의 特徵

李壽鐘 大韓法醫學會 1986 대한법의학회지 Vol.10 No.2

Along with increasing production of automobile in Korea, incidence of injured gravida is expected to rise in short period of time. This paper is attempted to review the literatures on trauma sustained from traffic accidents among pregnant women. Attention is particularly focussed on incidence, uniqueness of uterine injuries compared with other regions and impact on reproductive organ at the traffic accidents. Furthermore, differences in degree of injuries between users and non-users of safety belt and its working mechanisms are noted. As for pregnant women, three point belt is safer than lap belt whereas air bag is safer than belt for the benefit of fetus. Problems of human rights arising from artificial insemination still remain controversial from the social and ethical point of views. Once religious aspects of the problem is considered, the issue on in vitro fertilization is more contradictory and in complexity. Policy such as approval of adopted child discouraging artificial insemination should be re-evaluated considering barren couples amounting to 900,000, together with existing traditional value system on offsprings. Such conviction is enhanced considering individual is entitled to have a family. Furthermore, some state laws have legalized artificial insemination, and even tissue and organ banks have been established.

妊婦外傷의 合倂症과 後遺症

李壽鍾 大韓法醫學會 1980 대한법의학회지 Vol.4 No.1