• Journal for History of Mathematics
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• v.19 no.1
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• pp.65-78
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• 2006

The law of refraction, which is called Snell's law in physics, has a significant meaning in mathematics history. After Snell empirically discovered the refraction law $\frac{v_1}{sin{\theta}_1}=\frac{v_2}{sin{\theta}_2$ through countless observations, many mathematicians endeavored to deduce it from the least time principle, and the need to surmount these difficulties was one of the driving forces behind the early development of calculus by Leibniz. Fermat solved it far advance of others by inventing a method that eventually led to the differential calculus. Historically, mathematics has developed in close connection with physics. Physics needs mathematics as an auxiliary discipline, but physics can also belong to the lived-through reality from which mathematics is provided with subject matters and suggestions. The refraction law is a suggestive example of interrelations between mathematical and physical theories. Freudenthal said that a purpose of mathematics education is to learn how to apply mathematics as well as to learn ready-made mathematics. I think that the refraction law could be a relevant content for this purpose. It is pedagogically sound to start in high school with a quasi-empirical approach to refraction. In college, mathematics and physics majors can study diverse mathematical proof including Fermat's original method in the context of discussing the phenomenon of refraction of light. This would be a ideal environment for such pursuit.

• Korean Security Journal
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• no.10
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• pp.127-147
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• 2005

This study (research) has been done on the job, job-satisfaction and job dedication of body guards from many sectors in Korea. This research is focused on the relationship of job, job-satisfaction and job-dedication in diverse aspects in order to build up a detailed theory, As a result, teams of body guard can enhance their systematic efficiency through the theory. Therefore in this chapter, it will re-examine the result of this research and discuss about the theoretical and practical aspect of the result. This study(research) will be the outset(start) for the organizational behavior study of the body guards in Korea. Especially, this research tries to distinguish the duty aspect and the general feature of the body guards, satisfaction along with the level of dedication. Therefore it will give the persons concerning the bodyguards many theoretical and practical points to consider. But there is a limitation as crossing research that in this research we didn't research in compensation for all internal body guards and accomplishment of research has achieved in a short-time. Though it will be necessary to accomplish in henceforth research, if at all possible, in compensation for all body guards and much more diverse security service classification, also for a long time extended vertical research.

• Korean Journal of Weed Science
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• v.8 no.2
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• pp.158-163
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• 1988

Several factors affecting emergence and tuber formation of lowland perennial weeds were studied at the Yeongnam Crop Experiment Station in 1988. Period of tuber germination start to final tuber varied by species. Eleocharis kuroguwai and Sagittaria trifolia required longer than 10 days at $30^{\circ}C$ for this while Cyperus serotinus and S. pygmaea needed about 4 days. Application of gibberellic acid shortened this period while Uniconazole application delayed. E. kuroguwai and C. serotinus had ability to emerge under 20cm depth placement. However, S. trifolia could not emerge under 15cm depth. All species decreased their growth with increase in planting depth. E. kuroguwai had least correlated between dry matter production and tuber formation. Clipping of above ground part negatively related with tuber formation eventhough the effect of clipping time was differed by species. The most critical clipping time was 60 days after eremergence (DAE) for E. kuroguwai and 90 DAE for C. serotinus. Covering of colored polyethylene film was also related with tuber formation with varing effects. In general, the order of effectiveness for tuber formation were black. orange. blue and red. Application of Uniconazole and Pachlobutrazol effectively controlled the formation of tuber of E. kuroguwai and this effect enhanced by early application.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.1208-1217
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• 2009

This research was conducted in an attempt to understand changes and growths of the self in on-line game world. Q methodology was used to investigate players in Mabinogi, which is an on-line game(MMORPG). Based on 57 behavior statements, Players distributed their changing experiences from when they were novices in on-line game world to the current state. In early start phase, they recognized that on-line game world was different from the reality. And they perceived their experiences in on-line game as separated from the real ones. However, as they spend more time in on-line game world, they began to realized that on-line game world is as real as the world because they function as an individual living in a society in both the game and the real world. They felt and learned that in on-line game life, they also need to follow the rules and order. In addition, trust and politeness were essential in order to live with other players. As time passed, the players realized that on-line game experiences have the same meanings and values as the real life ones. 3 types of self-changing patterns were found : Achievement change, Control change, and Relation change. The behavior patterns of the 3 types were then compared to Identify similarities and differences amongst them in psychological meanings and values in the on-line game life. This result illustrates that on-line game world can be defined as new behavioral setting or developmental context established by digital technology. In this new setting, people can experiment and understand their behavior patterns and also experience changes and growths of the self.

• The Korean Journal of Zoology
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• v.29 no.3
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• pp.201-207
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• 1986

The authors attempted to investigate the oxygen consumption rate of sexuals in the water-striders, Gerris paludum insuralis, at four temperature groups of 25, 30, 35 and $40^\\circ C$ in a series of studies on respiration of a heminetabolous insects. THe results are summarised as follows: (1) At $30^\\circ C$, the change of oxygen consumption rate according to the lapse of time was small in comparison with the other three temperature groups which shows a cyclic decreasing pattern. The rate during initial and final 5 minutes was much alike. Thereupon, the optimum temperature was regarded as $30^\\circ C$. (2) The oxygen consumption rate of male was higher than that of female. (3) The oxygen consumption rates at 25, 30, 35 and $40^\\circ C$ were 0.42, 0.49, 0.79 and 1.11 $\\mu$l/mg/h respectively. That is, the rate was increased as the temperature was increased. (4) The $Q_10$ of male showed a high value in the lower temperature interval ($25^\\circ C \\sim 35^\\circ C$), but the female showed a high value in the higher temperature interval ($30^\\circ C \\sim 40^\\circ C$). The mean $Q_10$ was 2.12. (5) The respiratory rate was decreased as the body weight was increased in the above fresh weight of 10mg and dry weight 5 mg. (6) The upper temperature threshold for respiration was $48.31^\\circ C$ and the lower temperature threshold was $17.68^\\circ C$. (7) The ceasing time of breathing at the other three temperature groups except $30^\\circ C$ was infered to be about 110 minutes after the start of experiment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.12
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• pp.2712-2716
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• 2011

The development of mobile phone is growing everyday according to the change of our age. Most of all, the birth of smart phone has gotten lots of attentions. The Smart Phone has not only nalogue functions for calling and receiving but also has many multiple-service functions satisfying the contemporary digital needs. Due to the smart phone, people could access to various and plenty information simply by touching it. It was Sep. 2011 that the number of smart phone users began to be more than 15,000,000. That number stands for the turning point of digital revolution. In Korea, both of "Omnia" from Samsung and "i-phone" from Apple came into the market near the end of 2009. That time was so called the full-scale first smart-phone war, and thinking of the time, it could be named as the explosive growth of smart phones. We can predict that the smart phone will influence the real life of human beings not only the mobile phone market. In this way, the smart phone has come deeply into our life day by day. For instance, more people can be able to get the informations of their trip for their leisure and free weekends through the smart phone. Thus, our study, began with the theme of "Korean islands trip", will start in the relationship with the Application-Services, "Islands" utilizing web-pictures.

• World Technopolis Review
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• v.4 no.1
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• pp.11-22
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• 2015

Globalization, increasing technological advancements and dynamic knowledge diffusion are moving our world closer together at a unique scale and pace. At the same time, our rapidly changing society is confronted with major challenges ranging from demographic to economic ones; challenges that necessitate highly innovative solutions, forcing us to reconsider the way that we actually innovate and create shared value. As such the linear, centralized innovation models of the past need to be replaced with new approaches; approaches that are based upon an open and collaborative, global network perspective where all innovation actors strategically network and collaborate, openly distribute their ideas and co-innovate/co-create in a global context utilizing our society's full innovation potential (Innovation 4.0 - Open Innovation 2.0). These emerging innovation paradigms create "an opportunity for a new entrepreneurial renaissance which can drive a Cambrian like explosion of sustainable wealth creation" (Curley 2013). Thus, in order to materialize this entrepreneurial renaissance, it is critical not only to value but also to actively employ this new innovation paradigms so as to derive community-driven shared value that stems from global innovation networks. This paper argues that there is a gap in existing business incubation model that needs to be filled, in that the innovation and entrepreneurship community cannot afford to ignore the emerging innovation paradigms and rely upon closed incubation models but has to adopt an "open incubation" (Ziouvelou 2013). The open incubation model is based on the principles of open innovation, crowdsourcing and co-creation of shared value and enables individual users and innovation stakeholders to strategically network, find collaborators and partners, co-create ideas and prototypes, share their ideas/prototypes and utilize the wisdom of the crowd to assess the value of these project ideas/prototypes, while at the same time find connections/partners, business and technical information, knowledge on start-up related topics, online tools, online content, open data and open educational material and most importantly access to capital and crowd-funding. By introducing a new incubation phase, namely the "interest phase", open incubation bridges the gap between entrepreneurial need and action and addresses the wantpreneurial needs during the innovation conception phase. In this context one such ecosystem that aligns fully with the open incubation model and theoretical approach, is the VOICE ecosystem. VOICE is an international, community-driven innovation and entrepreneurship ecosystem based on open innovation, crowdsourcing and co-creation principles that has no physical location as opposed to traditional business incubators. VOICE aims to tap into the collective intelligence of the crowd and turn their entrepreneurial interest or need into a collaborative project that will result into a prototype and to a successful "crowd-venture".

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.2
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• pp.159-169
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• 2016

The goats raised in the barn are usually fed on fresh grass. As dry forage can be stored for long periods in large amounts, dry forage feeding makes it possible to feed large numbers of goats in barns. This review explains the physiological factors involved in suppressing dry forage intake and the cause of drinking following dry forage feeding. Ruminants consume an enormous amount of dry forage in a short time. Eating rates of dry forage rapidly decreased in the first 40 min of feeding and subsequently declined gradually to low states in the remaining time of the feeding period. Saliva in large-type goats is secreted in large volume during the first hour after the commencement of dry forage feeding. It was elucidated that the marked suppression of dry forage intake during the first hour was caused by a feeding-induced hypovolemia and the loss of $NaHCO_3$ due to excessive salivation during the initial stages of dry forage feeding. On the other hand, it was indicated that the marked decrease in feed intake observed in the second hour of the 2 h feeding period was related to ruminal distension caused by the feed consumed and the copious amount of saliva secreted during dry forage feeding. In addition, results indicate that the marked decreases in dry forage intake after 40 min of feeding are caused by increases in plasma osmolality and subsequent thirst sensations produced by dry forage feeding. After 40 min of the 2 h dry forage feeding period, the feed salt content is absorbed into the rumen and plasma osmolality increases. The combined effects of ruminal distension and increased plasma osmolality accounted for 77.6% of the suppression of dry forage intake 40 min after the start of dry forage feeding. The results indicate that ruminal distension and increased plasma osmolality are the main physiological factors in suppression of dry forage intake in large-type goats. There was very little drinking behavior observed during the first hour of the 2 h feeding period most water consumption occurring in the second hour. The cause of this thirst sensation during the second hour of dry forage feeding period was not hypovolemia brought about by excessive salivation, but rather increases in plasma osmolality due to the ruminal absorption of salt from the consumed feed. This suggests the water intake following dry forage feeding is determined by the level of salt content in the feed.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.6
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• pp.2505-2510
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• 2014

Background: The standard radiotherapy (RT) fractionation practiced in India and worldwide is 50Gy in 25 fractions over 5 weeks to the chest wall or whole breast followed by tumour bed boost in case of breast conservation (BCS). A body of validated data exists regarding hypofractionation in breast cancer. We here report initial results for 135 patients treated at our center with the START-B type of fractionation. Materials and Methods: From May 2011 till July 2012, women with all stages of breast cancer (excluding metastatic), who had undergone BCS or mastectomy were planned for 40Gy in 15 fractions over 3weeks to chest wall/whole breast and supraclavicular fossa (where indicated) followed by tumour bed boost in BCS patients. Planning was done using Casebow's technique. The primary end point was to assess the acute toxicity and the cosmetic outcomes. Using cosmetic scales; patients were assessed during radiotherapy and at subsequent follow up visits with the radiation oncologist. Results: Of the 135 patients, 62 had undergone BCS and 73 mastectomy. Median age of the population was 52 years. Some 80% were T1&T2 tumours in BCS whereas most patients in mastectomy group were T3&T4 tumours (60%). 45% were node negative in BCS group whilst it was 23% in the mastectomy group. Average NPI scores were 3.9 and 4.9, respectively. Most frequently reported histopathology report was infiltrating ductal carcinoma (87%), grade III being most common (58%), and 69% were ER positive tumours, and 30% were Her 2 Neu positive. Triple negative tumours accounted for 13% and their mean age was young (43 yrs.) The maximum acute skin toxicity at the end of treatment was Grade 1 in 94% of the mastectomy grouppatients and 71% in BCS patients. Grade 2 toxicity was 6% in mast group and 23% in BCS group. Grade 3 was 6% in BCS group, no grade 3 toxicity in mastectomy patients and there was no grade 4 skin toxicity in any case. Post RT at 1 month; 39% of BCS patients had persisting Grade I skin reaction which was only 2% in mastectomy patients. At 3 months post RT, 18% patients had persisting hyperpigmentation. At 6 months 8% patients had persisting erythema in the BCS group only. Some 3% BCS and 8% mastectomy patients had lymph edema till the date of evaluation. Cosmetic outcome in BCS patients remained good to excellent 6 months post surgery and radiotherapy. 1 patient of BCS and 3 patients of mast had developed metastatic disease at the time of evaluation. Conclusions: Hypofractionated RT is well tolerated in Indian population with reduced acute skin toxicity and good cosmetic outcome. Regimens such as these should be encouraged in other centers to increase machine output time. The study is on-going to assess long term results.

• Clinical and Experimental Pediatrics
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• v.46 no.9
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• pp.893-897
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• 2003

Purpose : Benign childhood epilepsy with centrotemporal spikes(BECT) is characterized by an excellent prognosis. Therefore, the necessity for the use of antiepileptic drugs is controversial. The object of this study is to know about the long-term follow-up of BECT, comparing daily treatment with antiepileptic drug(AED) versus no medication. Methods : We retrospectively studied 56 cases of BECTs, examined at Pediatric Neurology Clinic, Korea University Medical Center as reference study time, August 2002. Thirty-eight patients didn't have mediation(group I), while eighteen patients received one or two AED(group II). We evaluated demographics, clinical manifestations at diagnosis, EEG findings and clinical courses in groups I & II. Results : There was no significant differences of sex, age, seizure frequency, seizure type, seizure onset time, family history and EEG findings between group I & II. The reasons to start AED were : parents' anxiety(three cases), frequent seizure(12 cases) and daytime seizure(three cases). There was no evolution of status epilepticus and no difficulty in school performance. Conclusion : AED treatment was of no advantage and long-term prognosis was good regardless of treatment strategy. So it is advisable not to choose AED as the first line of therapy, provided that the patient himself/herself or the family understands the benign nature of BECT.