• Korea-Australia Rheology Journal
• /
• v.19 no.3
• /
• pp.125-131
• /
• 2007

Biodegradable polymeric blends are expected to be widely used by industry due to their environmental friendliness and comparable mechanical and thermal properties. Poly (lactic acid) (PLA) and poly (butylene succinate) (PBS) are such biodegradable polymers which aim to replace commodity polymers in future applications. Since cost and brittleness of PLA is quite high, it is not economically feasible to use it alone for day to day use as a packaging material without blending. In this study, blends of PLA and PBS with various compositions were prepared by using a laboratory-scale twin-screw extruder at $180^{\circ}C$. Morphological, thermal, rheological and mechanical properties were investigated on the samples obtained by compression molding to explore suitability of these compositions for packaging applications. Morphology of the blends was investigated by scanning electron microscopy (SEM). Morphology showed a clear phase difference trend depending on blend composition. Modulated differential scanning calorimetry (MDSC) thermograms of the blends indicated that the glass transition temperature ($T_g$) of PLA did not change much with the addition of PBS, but analysis showed that for PLA/PBS blend of up to 80/20 composition there is partial miscibility between the two polymers. The tensile strength and modulus were measured by the Instron Universal Testing Machine. Tensile strength, modulus and percentage (%) elongation at break of the blends decreased with PBS content. However, tensile strength and modulus values of PLA/PBS blend for up to 80/20 composition nearly follow the mixing rule. Rheological results also show miscibility between the two polymers for PBS composition less than 20% by weight. PBS reduced the brittleness of PLA, thus making it a contender to replace plastics for packaging applications. This work found a partial miscibility between PBS and PLA by investigating thermal, mechanical and morphological properties.

• Journal of the Korea Society of Computer and Information
• /
• v.13 no.3
• /
• pp.147-152
• /
• 2008

Ant System(AS) is new meta heuristic for hard combinatorial optimization problem. It is a population based approach that uses exploitation of positive feedback as well as greedy search. It was first proposed for tackling the well known Traveling Salesman Problem. In this paper, AS is applied to the Multicast Routing Problem. Multicast Routing is modeled as the NP-complete Steiner tree problem. This is the shortest path from source node to all destination nodes. We proposed new AS to resolve this problem. The proposed method selects the neighborhood node to consider all costs of the edge and the next node in state transition rule. Also, The edges which are selected elite agents are updated to additional pheromone. Simulation results of our proposed method show fast convergence and give lower total cost than original AS and $AS_{elite}$.

• Korean Journal of Legislative Studies
• /
• v.22 no.2
• /
• pp.157-188
• /
• 2016

Since democratic transition in the early 1990s, constitutionalism is getting more important for democratic consolidation in Africa. Using Afribarometer data set, this paper explains influences on public confidence in judiciary. High levels of public trust in judiciary is a necessary condition for judicial system to work effectively in emerging democracy. Unlike existing studies focusing on the function of judiciary and legal procedures, this paper is interested in the relationship between how ordinary Africans perceive the attitudes of the chief executive toward judiciary, the rule of law, and judicial corruption and their confidence in judiciary. The results show that those who think that the chief executive is likely to respect the constitution and the judiciary, that the law applies to everyone equally, and that there are few corrupt judicial personnel are likely to show high levels of confidence in judiciary. This study argues that the tension between laws and politics have a significant influence on transitional justice in emerging democracy.

• Korean Linguistics
• /
• v.71
• /
• pp.1-22
• /
• 2016

The early 20th century is a period of time when Korea confronted with the surging waves of modernization, and made a variety of internal reactions. The Korean language, not immune to the upheaval, also experienced new changes and gradually gained characteristics of today's Korean. Although scholars have not yet fully agreed upon the time division of Korean, Gabo reformation (1896) is usually considered to be the beginning of modern Korean. Thus, the early 20th century was also the beginning of modern Korean. Phonological, lexical, and grammatical characteristics of modern day Korean began to appear during this period of time. Phonologically, the 10 vowel system was established, glottal sounds and aspirated sounds increased, vowel harmony declined. Phenomena such as vowel raising, front-vowelization, monophthongization, and the word-initial rule appeared. Meanwhile, hangul-Chinese mix writing became common practice, and hangul-only writing also started to take place in narrative writing, and elements of spoken language began to reflect in written language. All those pointed to the unification of written and spoken language. Under the influence of modernization, a great amount of new words appeared. Especially, Japanese and other foreign words flooded in in great quantities. Grammatically, '-eos-(-엇-), -neun-(-는-), -ges-(-겟-)' trichotomy system of tenses was established, and hearer-oriented honorific system also formed a binary system of 'hasoseo(하소서), hasibsio(하십시오), hao(하오), hage(하게), haera(해라)' and 'hae (해), haeyo(해요)'. In word formation and sentence construction, the use of '-gi(-기)' became more frequent than '-eum(-음)', while '~geot(~것)' also significantly increased. In negative, causative and passive expressions, the use of long form, which has fewer restrictions than the short form, became more frequent. A tendency towards simplicity appeared. In the same vain, long and complex sentences with several clauses tend to be avoided. Instead, short simple sentences became more favorable. Korean linguistics scholars should pay closer attention to the modernization period, which includes the early 20th century. In order to fully understand today's Korean language, more thorough research on this immediately preceding period is necessary.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.14 no.2
• /
• pp.439-446
• /
• 2019

In this paper, we propose a encryption method using C-MLCA and 1D CAT to secure medical image for efficiently. First, we generate a state transition matrix using a Wolfram rule and create a sequence of maximum length. By operating the complemented vector, it converts an existing sequence to a more complex sequence. Then, we multiply the two sequences by rows and columns to generate C-MLCA basis images of the original image size and go through a XOR operation. Finally, we will get the encrypted image to operate the 1D CAT basis function created by setting the gateway values and the image which is calculated by transform coefficients. By comparing the encrypted image with the original image, we evaluate to analyze the histogram and PSNR. Also, by analyzing NPCR and key space, we confirmed that the proposed encryption method has a high level of stability and security.

• The Southeast Asian review
• /
• v.23 no.1
• /
• pp.235-276
• /
• 2013

Recent incidents of lethal violence in the Rakhine State of Myanmar between the majority Buddhist Rakhine and the Muslim Rohingya have been the source of much concern for the international community. Unlike the past, the killings and incendiary attacks by both communities have intensified to a critical level, proving to be a great liability for the forward-thinking Myanmar government, whose recent transition to civilian rule after a long military one has made it eager to move on. The roots of the conflict trace back to the military regime, who branded the Rohingyas living in Rakhine state as illegal immigrants and refused to confer upon them official recognition as Myanmar citizens. The discord then moved to an ethnic conflict, pitting the Rohingya not merely against the Myanmar government but rather the majority Buddhist Rakhine. The conflict, as it has developed into the present, is an immensely complicated one that simultaneously encompasses ethnic and religious issues, all intertwined together. This study aims to see how the two ethnic groups have come to resort to such violence, despite having lived in each other's presence for many centuries, and why the violence persists. It will attempt to reconcile the fact that Rakhine had historically been a place of convergence for two groups, the Buddhist Rakhine and the Rakhine Muslim(the Rohingya). Based on the argument, this study also seeks to uncover, identify, and understand the Rohingya identity with the extreme arguments exhibited by both sides, and from there, locate the underlying causes of the greater religio-ethnic conflict in Rakhine that has so ravaged the place as of recent.

• The Journal of the Korea Contents Association
• /
• v.22 no.1
• /
• pp.348-358
• /
• 2022

The purpose of this study is to produce visual content for effective education of Passive verbs and Causative verbs in Korean language education for foreigners. Passive verbs and causative verbs are contents that must be taught to intermediate level learners. However, it is recognized as a difficult item for both learners and Korean teachers because the realization pattern is complicated, and there is no rule to explain the combination relationship between the action and the instruction by suffix. In this article, the use of nonverbal information that can improve the learning effect was considered. Providing verbal and non-verbal information together in language education can be expected to improve learners' communication skills. In particular, visual content is non-verbal information that can positively affect memory enhancement, playback, and transition. Therefore, this study attempted to plan and produce picture cards as visual materials. The picture card, produced with a focus on the correct education of Korean Passive verbs, will efficiently and significantly make Korean Passive verbs and Causative verbs teaching and learning by suffixes.

• The Korean Journal of Air & Space Law and Policy
• /
• v.29 no.1
• /
• pp.67-95
• /
• 2014

Some Contracting States of the Chicago Convention issue FAOC(Foreign Air Operator Certificate) and conduct various safety assessments for the safety of the foreign operators which operate to their state. These FAOC and safety audits on the foreign operators are being expanded to other parts of the world. While this trend is the strengthening measure of aviation safety resulting in the reduction of aircraft accident. FAOC also burdens the other contracting States to the Chicago Convention due to additional requirements and late permission. EASA(European Aviation Safety Agency) is a body governed by European Basic Regulation. EASA was set up in 2003 and conduct specific regulatory and executive tasks in the field of civil aviation safety and environmental protection. EASA's mission is to promote the highest common standards of safety and environmental protection in civil aviation. The task of the EASA has been expanded from airworthiness to air operations and currently includes the rulemaking and standardization of airworthiness, air crew, air operations, TCO, ATM/ANS safety oversight, aerodromes, etc. According to Implementing Rule, Commission Regulation(EU) No 452/2014, EASA has the mandate to issue safety authorizations to commercial air carriers from outside the EU as from 26 May 2014. Third country operators (TCO) flying to any of the 28 EU Member States and/or to 4 EFTA States (Iceland, Norway, Liechtenstein, Switzerland) must apply to EASA for a so called TCO authorization. EASA will only take over the safety-related part of foreign operator assessment. Operating permits will continue to be issued by the national authorities. A 30-month transition period ensures smooth implementation without interrupting international air operations of foreign air carriers to the EU/EASA. Operators who are currently flying to Europe can continue to do so, but must submit an application for a TCO authorization before 26 November 2014. After the transition period, which lasts until 26 November 2016, a valid TCO authorization will be a mandatory prerequisite, in the absence of which an operating permit cannot be issued by a Member State. The European TCO authorization regime does not differentiate between scheduled and non-scheduled commercial air transport operations in principle. All TCO with commercial air transport need to apply for a TCO authorization. Operators with a potential need of operating to the EU at some time in the near future are advised to apply for a TCO authorization in due course, even when the date of operations is unknown. For all the issue mentioned above, I have studied the function of EASA and EU Regulation including TCO Implementing Rule newly introduced, and suggested some proposals. I hope that this paper is 1) to help preparation of TCO authorization, 2) to help understanding about the international issue, 3) to help the improvement of korean aviation regulations and government organizations, 4) to help compliance with international standards and to contribute to the promotion of aviation safety, in addition.

• Journal of Korean Society of Transportation
• /
• v.20 no.5
• /
• pp.113-130
• /
• 2002

In this paper, we developed DNL(Dynamic Network Loading) model based on Moving cell theory to analyze the dynamic characteristics of traffic flow in congested network. In this paper vehicles entered into link at same interval would construct one cell, and the cells moved according to Cell following rule. In the past researches relating to DNL model a continuous single link is separated into two sections such as running section and queuing section to describe physical queue so that various dynamic states generated in real link are only simplified by running and queuing state. However, the approach has some difficulties in simulating various dynamic flow characteristics. To overcome these problems, we present Moving cell theory which is developed by combining Car following theory and Lagrangian method mainly using for the analysis of air pollutants dispersion. In Moving cell theory platoons are represented by cells and each cell is processed by Cell following theory. This type of simulation model is firstly presented by Cremer et al(1999). However they did not develop merging and diverging model because their model was applied to basic freeway section. Moreover they set the number of vehicles which can be included in one cell in one interval so this formulation cant apply to signalized intersection in urban network. To solve these difficulties we develop new approach using Moving cell theory and simulate traffic flow dynamics continuously by movement and state transition of the cells. The developed model are played on simple network including merging and diverging section and it shows improved abilities to describe flow dynamics comparing past DNL models.

• Investigative Magnetic Resonance Imaging
• /
• v.3 no.2
• /
• pp.179-187
• /
• 1999

Purpose : This paper introduces a computationally inexpensive context-dependent classification of multi-echo MRI with Bayes compound decision model. In order to produce accurate region segmentation especially in homogeneous area and along boundaries of the regions, we propose a classification method that uses contextual information of local enighborhood system in the image. Material and Methods : The performance of the context free classifier over a statistically heterogeneous image can be improved if the local stationary regions in the image are disassociated from each other through the mechanism of the interaction parameters defined at he local neighborhood level. In order to improve the classification accuracy, we use the contextual information which resolves ambiguities in the class assignment of a pattern based on the labels of the neighboring patterns in classifying the image. Since the data immediately surrounding a given pixel is intimately associated with this given pixel., then if the true nature of the surrounding pixel is known this can be used to extract the true nature of the given pixel. The proposed context-dependent compound decision model uses the compound Bayes decision rule with the contextual information. As for the contextual information in the model, the directional transition probabilities estimated from the local neighborhood system are used for the interaction parameters. Results : The context-dependent classification paradigm with compound Bayesian model for multi-echo MR images is developed. Compared to context free classification which does not consider contextual information, context-dependent classifier show improved classification results especially in homogeneous and along boundaries of regions since contextual information is used during the classification. Conclusion : We introduce a new paradigm to classify multi-echo MRI using clustering analysis and Bayesian compound decision model to improve the classification results.