• The korean journal of orthodontics
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• v.30 no.4 s.81
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• pp.467-473
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• 2000

As a rectangular wire Is inserted into edgewise brackets the wire exerts a force system three-dimensionally. The force system may include bending force in first and second orders and a torsional force in third order Analytical and experimental studies on bending force have been Introduced, but information about torsion is still lack. The purpose of this study was to estimate the torsional moment in the force system of rectangular arch wires through theoretical and experimental studies. Wires most frequently used for third order control were selected as study materials. Cross sections of 0.016x0.022, 0.017x0.025, 0.019x0.025 inch rectangular wires in foot different materials such as stainless steel(Ormco), TMA(Ormco), NiTi(Ormco), and braided stainless steel (DentaFlex, Dentaurum) were used. The torque/twist rate of each test material was calculated using the torsion formula. Torque/twist rate, yield torsional moment, and ultimate torsional moment were measured with a torque gauge. The torsion formula assesses that the torque/twist rate (T/$\theta$) is proportional to the characteristics of material (G) and cross section (J), and is inversely proportional to the length of wire (L). Most experimental results corresponded with the formula. The relative stiffness was calculated for reference to a logical sequence of wire changes.

• Journal of Sericultural and Entomological Science
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• v.50 no.2
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• pp.178-188
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• 2012

Since based on the 7th revised educational curriculum, the insects and spiders in elementary school textbook are as follows. A total of 60 species belonging to ten order of insects and three species of two families in the order Araneae were investigated. Among of them, we found that the species name and their photos were switched in three times, and also, misidentified species name were examined in three times. In the result of spices appearing frequencies between insects and spiders in the whole grade levels, the confirmed species numbers were a total of 63 species and the number of frequencies were 169 times. In the appearing frequencies, the correct identified species are relatively lowed as only 44 times(26.0%). In investigation on the appearing frequencies for the each insect orders, Othoptera and Coleoptera are mostly high such as ten and nine times, respectively. The appearing frequency for species levels are sequently counted as Drosophila sp.(18 times), Oxya chinensis sinuosa(16 times), and Papilio xuthus(12 times). The result of investigation for the appearing frequencies of insects in the each grades and semesters indicated that the first semester of third grade includes most large number insects which are 18 insect species, contrary, only one insect species are reported in the first semester of second grade.

• Journal of Platform Technology
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• v.9 no.3
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• pp.3-17
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• 2021

Advanced persistent threat (APT) attacks are attacks aimed at a particular entity as a set of latent and persistent computer hacking processes. These APT attacks are usually carried out through various methods, including spam mail and disguised banner advertising. The same name is also used for files, since most of them are distributed via spam mail disguised as invoices, shipment documents, and purchase orders. In addition, such Infostealer attacks were the most frequently discovered malicious code in the first week of February 2021. CDR is a 'Content Disarm & Reconstruction' technology that can prevent the risk of malware infection by removing potential security threats from files and recombining them into safe files. Gartner, a global IT advisory organization, recommends CDR as a solution to attacks in the form of attachments. There is a program using CDR techniques released as open source is called 'Dangerzone'. The program supports the extension of most document files, but does not support the extension of HWP files that are widely used in Korea. In addition, Gmail blocks malicious URLs first, but it does not block malicious URLs in mail systems such as Naver and Daum, so malicious URLs can be easily distributed. Based on this problem, we developed a 'Dangerzone' program that supports the HWP extension to prevent APT attacks, and a Chrome extension that performs URL checking in Naver and Daum mail and blocking banner ads.

• The Journal of Korean Philosophical History
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• no.36
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• pp.259-291
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• 2013

This article is to study the purpose and significance of Chongyoulun of Peiwei, and it is composed of the two parts of philosophy and critical mind. The critical mind on Chongyoulun is as follows: first, it is mis-interpretative to define the main thought of Laozi as Xuwu. Next, the old philosophers did not criticize Xuwuism properly; as a result, they failed to stop spreading Xuwuism. Last, Guiwulun brought about the disorder of the way of life and the collapse of the public order. Based on this critical mind, Peiwei built up the following philosophy based on You as the fundamental principle of the existence and the movement of universal nature. First, Tao is the combined Wanyou, not abstract substance which is outside of Wanyou. Second, Wu is the state of being without You, and You only comes from You. Third, You can survive depending on external You because You is not the independent substance. Therefore, understanding the external You is the main factor of its existence. Fourth, Wanyou do not harm each other as they get together since Wanyous are interdependent. People are the being who can live through the mutual dependent relationships; hence, social system and morals (ethics) are key factors of the world in the oncological point of view. Wanyou had tried to rebuild the corrupted way of life and public order by recovering the justification of moral orders based on the mutual dependence of Wanyou which is the substance character.

• The Journal of Information Systems
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• v.30 no.1
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• pp.151-177
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• 2021

Purpose This paper aims to improve management performance by effectively responding to production needs and reducing inventory through synchronizing production planning and procurement in the aviation industry. In this study, the differences in production planning and execution were first analyzed in terms of demand, supply, inventory, and process using the big data collected from a domestic aircraft manufacturers. This paper analyzed the problems in procurement and inventory management using legacy big data from ERP system in the company. Based on the analysis, we performed a simulation to derive an efficient procurement and inventory management plan. Through analysis and simulation of operational data, we were able to discover procurement and inventory policies to effectively respond to production needs. Design/methodology/approach This is an empirical study to analyze the cause of decrease in inventory turnover and increase in inventory cost due to dis-synchronize between production requirements and procurement. The actual operation data, a total of 21,306,611 transaction data which are 18 months data from January 2019 to June 2020, were extracted from the ERP system. All them are such as basic information on materials, material consumption and movement history, inventory/receipt/shipment status, and production orders. To perform data analysis, it went through three steps. At first, we identified the current states and problems of production process to grasp the situation of what happened, and secondly, analyzed the data to identify expected problems through cross-link analysis between transactions, and finally, defined what to do. Many analysis techniques such as correlation analysis, moving average analysis, and linear regression analysis were applied to predict the status of inventory. A simulation was performed to analyze the appropriate inventory level according to the control of fluctuations in the production planing. In the simulation, we tested four alternatives how to coordinate the synchronization between the procurement plan and the production plan. All the alternatives give us more plausible results than actual operation in the past. Findings Based on the big data extracted from the ERP system, the relationship between the level of delivery and the distribution of fluctuations was analyzed in terms of demand, supply, inventory, and process. As a result of analyzing the inventory turnover rate, the root cause of the inventory increase were identified. In addition, based on the data on delivery and receipt performance, it was possible to accurately analyze how much gap occurs between supply and demand, and to figure out how much this affects the inventory level. Moreover, we were able to obtain the more predictable and insightful results through simulation that organizational performance such as inventory cost and lead time can be improved by synchronizing the production planning and purchase procurement with supply and demand information. The results of big data analysis and simulation gave us more insights in production planning, procurement, and inventory management for smart manufacturing and performance improvement.

• Journal of Korea Entertainment Industry Association
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• v.15 no.4
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• pp.243-254
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• 2021

This study analyzed the abuse of authority among the types of power abuse in educational institutions in order to create an educational climate in which democracy and equality are respected and to create a better education and an equal society. First, we analyzed the concept and cause of power abuse through literature research, and then explored the cases of members of educational institutions according to the type of abuse of authority through qualitative research to derive implications. As a result, abuse of authority within educational institutions were found as follows: additional work without consultation, transfer of duties, coercive and unilateral instructions using status, instructions violating laws and guidelines, private instructions for personal convenience, specific institutions, personal rights, and privacy. Based on this analysis, a policy was proposed. First, an agreed standard for abuse of authority, an institutional mechanism to mediate conflicts and complaints over abuse of authority, mandatory installation and legislation of the best decision body, active and transparent disclosure of information, and a shift to open and listening administration are needed. Second, analyzing and seeking ways to reduce overuse of authority in educational institutions will be the cornerstone for leading education's democracy and equality by creating a culture of mutual respect and communication among members of the organization. Hope that follow-up studies will be carried out and that the Gap-jil in educational institutions will be reduced to create a better educational environment.

• Animal Systematics, Evolution and Diversity
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• v.11 no.1
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• pp.39-64
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• 1995

A faunistic and ecological study on the occurrence of freshwater cladocerans and copepods was accomplished from Chindo, South Korea. Collections were made from total 35 stations, comprising the various freshwater habitats like reservoirs, streams, swamps, bogs, ricefields, ditch, pond, and spring during the periods of July 23-25, and November 1-3 in 1994. Twenty seven cladoceran species of 17 genera of 6 families in 2 orders, and 28 copepod species of 21 genera of 6 families in 3 orders were collected during this research period, of which Daphnia obtusa Kurz and Elaphoidella bidens (Schmeil) are newly recorded from Korea. In reservoirs, Diaphanosoma sp. and Thermocyclops taihokuensis were dominant in July, and then succeeded by Bosmina longirostris and Cyclops vicinus vicinus in November. Thermocyclops crassus co-occurred with 7: taihokuensis at both seasons, was frequent in November after T. taihokuensis precipitately decreased. In other stagnant waters, 7: taihokuensis and Moina weismanni were dominant at ponds in July and in November, respectively. At ricefields in July Moina macrocopa and T. taihokuensis were dominant, but in November M. macrocopa and Paracyclops fimbriatus were. At streams, cladocerans were relatively rare, but became more rich in November. The representative cladoceran species were Bosmina longirostris as a plankton, and Chydorus sphaericus as a epibenthic species. Concerning copepods, nearly all the stations of streams except a few ones adjacent to seashore showed the similiar species constitutions, of which E. serrulatus and M, pehpeiensis were most frequent and abundant. At a mountain streamlet and a spring, the occurrence of Alona sp., Attheyella byblis Chang and Kim, 1992 and A. tetraspinosa Chang, 1993 is quite interesting and deserved much attention in the taxonomical point of view. Seventeen major cladocerans and copepods from lentic habitats and 13 major cladocerans and copepods from lotic habitatats were clustered using average taxonomic distance and UPGMA to infer the co-occurrence relations among species. As for lentic habitats, two large phena were appeared at first. The one phenon consisted of Diaphanosoma sp. and T taihokuensis, and showed its predominancy over the various habitats and its dominancy was rapidly decreased in November. The other phenon frequently occurred rather in November, and subdivided into three subgroups. On the other hand, as for lotic habitats, 13 species were also grouped into 2 large phena. The first one comprised 4 species, which were dominant and highly frequent at nearly all the lotic habitats, and subdivided into three subgroups according to their seasonal fluctuation types. The second one was also subdivided into three phena, the first of which comprised only one species, Microcyclops varicans, and occurred at most of the stations along stream with steadiness through the research period; the second phenon, Chydorus sphaericus, occurred much frequently in November; the last phenon included a few heterogenous subgroups.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.4
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• pp.343-358
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• 2011

As implant treatment has become popular, lots of different shapes and materials of the implant upper component have been supplied. And there are also diverse reports about failures including loosening of the abutment screw which is one of the most common reason. Purpose : The purpose of this study is to find out how different screw tightening orders and methods influence on screw loosening according to the different connection systems. The upper component was fabricated by casting method. After fabricating master models that are precisely attached to the upper component, 5 experimental models each for the external connection system and internal connection system were fabricated using splinting impression technique. First, to find out the influence of the screw tightening order, screws were tightened in 3 orders; 1-2-3-4, 2-3-1-4, 2-4-3-1. After tightening, removal torque values (RTV) of each group was measured. And also to find out the influence of screw tightening method, a model with 2-3-1-4 screw tightening order was tightened with 30 Ncm at one time(1-step method) and the RTV was compared with the same order group (2-3-1-4) in the 2 step method. In the external connection system, RTV appeared significantly lower in group 2-3-1-4 than group 2-4-3-1 (p<0.05). And also in the internal connection system, the RTV of group 2-3-1-4 appeared significantly lower than that of group 2-4-3-1 and 1-2-3-4 (p<0.05). When comparing the tightening number of the screw without considering the screw tightening order, the first tightened screw appeared significantly higher RTV than the second one in the external connection system (p<0.05), however there was no significant difference from the first tightened screw to the last tightened screw in the internal connection system. And there was no statistically significant difference between the two screw tightening methods in both internal and external connection system. In the comparison of external and internal connection system, each RTV appeared 16.27 Ncm and 14.25 Ncm and appeared as a statistically significant difference (p<0.05). There was a significant difference in RTV measured according to the screw tightening order. The lowest RTV appeared in the groups started tightening from the middle. There was also a significant difference in RTV between the two connection system groups. A further study is needed to find out the influence factors in RTV and also a study is required related to the load condition.

• Tuberculosis and Respiratory Diseases
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• v.44 no.4
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• pp.889-898
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• 1997

Pulmonary Embolism can develop in variable conditions, and presents with nonspecific symptoms and signs. If diagnosis is delayed, it can be resulted in catastrophic results. Therefore, early diagnosis and adequate treatment is crucial in Pulmonary Embolism. Lung Perfusion Scan is useful screening test. Negative result can exclude pulmonary embolism. But, perfusion defects don't always mean pulmonary embolism. To find the better methods of interpretation of lung perfusion scan and To evaluate the clinical course and outcomes of the patients, in whom pulmonary embolism was suspected by lung perfusion scan, we reviewed the clinical records of 49 cases suspected by lung perfusion scan at Seoul National University Hospital during the period of January, 1995 to July, 1996. The results are as follows. First impression of cases in which PE was present at time of admission were pulmonary embolism (63%), heart diseases (26%), and pneumonia (11%) in orders. Underlying diseases of cases in which PE developed during admission were malignancy (36.5%), ICH (22.7%), sepsis (13.7%), and SLE (9.1%) in orders. The predisposing factors were operation (20%), cancer (16%), immobility (16%), connective tissue disease (16%), heart dis. (10%), old age (10%), and preg/pelvic dis. (8%) The results, of lung perfusion scan were HPPE 40 cases(26.8 %), IPPE 21 cases(14.1%), LPPE 88 cases (59.1%), and cases(%) of treatment in these cases were HPPE 34 cases(85%), IPPE 9 cases(42.9%), LPPE 0 case(0.0%). Treatments were heparin and warfarin (69.5%), heparin alone (8.2%), warfarin alone (2.0%), embolectomy (4.1%), thrombolytics (2.0%), IVC filter (2.0%), and no treatment (12.2%) In 34 cases (69.4%), follow up could be done, and 5 cases were recurred (10.2%). The causes of recurrence was incomplete anticoagulant therapy (3 cases) and recurrence of predisposing factor (2 cases). Expired case due to pulmonary embolism was one who was expired just before trial of thrombolytic therapy. Conclusion : Efforts should be made to shorten the interval from onset of Sx to Dx, ie, high index of suspision.

• The Korean Journal of Air & Space Law and Policy
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• v.1
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• pp.193-222
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• 1989

The purpose of this study is to review the rights and duties of cargo owners, the party to the contract of international carriage of goods by air under the Warsaw Convention System and the IATA conditions. It is generally known that air freight is the most-cost mode of transportation. However, should there be considerations of total distribution cost, the use of air freight leads exporters to be advantageous in physical distribution. The Warsaw Convention System defined and limited the rights and duties of cargo owners and air carriers paticipating in the international carriage of goods, but it does not regulate every aspect of air transportation. Therefore, the unregulated parts are governed by national laws and by individual contracts of carriage. The International Air Transport Association(lATA), a worldwide organization of airlines, has formulated model conditions of contract for the carriage of cargo. These models are not uniformly followed but they serve as a basis for many of the individual standard form of contracts prepared by air carriers. The contract of air carriage of goods is a contract of adhesion, 'the consignor recognizing and accepting the conditions laid down by the carrier'. There are consignors and carriers as the parties to the contract of international carriage of goods. In addition to his basic right, implied in Warsaw Convention Article 18 and 19, to require devery of the goods in good condition and at the date agreed upon, the consignor has the right to dispose the goods in the course of the journey up to the moment when the consignee is entitled to require delivery. If it is impossible to carry out the orders of the consignor, the carrier must so inform him forthwith. The right conferred on the consignor ceases at the moment when that of the consignee begins in accordance with Warsaw Convention Article 13. Nevertheless, if the consignee declines to accept the air waybill or the goods, or if he cannot be communicated with, the consignor resumes his right of disposition. Unless it is otherwise agreed, it is the duty of the carrier to give notice to the consignee as soon as the goods arrive. The consignee is entitled, on arrival of the goods at the place of destination, to require the carrier to hand over to him the air waybill and to deliver the goods to him, on payment of the charges due and on complying with the conditions of carriage set out in the air waybill. The air waybill is supposed to be made out by the consignor. If the carrier makes it out, he is deemed, subject to proof to the contrary, to have done so on behalf of the consignor, whether there is one air waybill or several, each must be made out in three original parts. The first is for the carrier, the second is for the consignee, and the the third is handed to the consignor when the shipment has been accepted. The consignor is responsible for the correctness of the particulars and statement concerning the cargo appearing in the air waybill. Each of the original parts of the air waybill has evidential value and possession of his part is a condition for the exercise by the consignor or consignee of his rights under the contract of carriage. Hague Protocol set forth in Article 9 that nothing in this. Convention prevents the issue of a negotiable air waybill, but Montreal Additional Protocol No. 4 deleted this article. All charges applicable to a shipment are payable in cash at the time of acceptance thereof by the carrier in case of a prepaid shipment or at the time of delivery thereof by the carrier in case of a collect shipment. The carrier shall have lien the cargo for unpaid charges and, in the event of non-payment thereof, shall have the right to dispose of the cargo at public or private sale and pay itself out of the proceeds of such sale any and all such amounts. In conclusion, the Warsaw Convention System has the character of ambiguity in various respects, not only in the part of the forms of documents but also in conditions of contract. Accordingly, the following propositions might be considered: (1) If the carrier does not obey the orders of the consignor for the disposition of the goods without proper reasons, he will be liable strictly for any damage which may be caused thereby to the cargo owner. The special agreement and carrier's conditions of carriage which limit unreasonably the consignor's right of disposition of the goods will be nullified. (2) The instrument of the Warsaw Convention System which is not yet in force(Montreal Additional Protocol No. 4) would considerably simplfy the processing and keeping of computerized records of the carriage. Until this instrument enters into force, the airlines will be faced with practical problems preventing them to substitute computerized data processing techniques for the formal issuance of the documents. Accordingly, Montreal Additional Protocol No. 4 should become effective as soon as posisble. From a practical point of view in the international trade, the issuance of negotiable air waybill should be permitted for the security of the bank.