• Restorative Dentistry and Endodontics
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• v.35 no.5
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• pp.380-386
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• 2010

Objectives: The introduction of nickel-titanium alloy endodontic instruments has greatly simplified shaping the root canal systems. However, these new instruments have several unexpected disadvantages. One of these is tendency to screw into the canal. In this study, the influence of taper on the screw-in effect of the Ni-Ti rotary instrument were evaluated. Materials and Methods: A total of 20 simulated root canals with an S-shaped curvature in clear resin blocks were divided into two groups. ProFile .02, .04, .06 (Dentsply-Maillefer) and GT rotary files .08, .10, .12 (Dentsply) were used in Profile group, and K3 .04, .06, .08, .10, and .12 (SybronEndo, Glendora) were used in K3 group. Files were used with a single pecking motion at a constant speed of 300 rpm. A special device was made to measure the force of screw-in effect. A dynamometer of the device recorded the screwin force during simulated canal preparation and the recorded data was stored in computer with designed software. The data were subjected to one-way ANOVA and Tukey's multiple range test for post-hoc test. p value of less than 0.05 was regarded significant. Results: The more tapered instruments generated more screw-in forces in Profile group (p < 0.05). In K3 group, 0.08, 0.10. and 0.12 tapered instruments showed more screw-in force than 0.04 tapered one, and 0.08 and 0.12 tapered instruments showed more screw-in force than 0.06 tapered one (p < 0.05). Conclusions: The more tapered instruments seems to produce more screw-in force. To avoid this screw-in force during instrumentation, more attention may be needed when using more tapered instruments.

• Journal of the Korean Geographical Society
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• v.28 no.4
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• pp.379-391
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• 1993

Present-day world economy is characterized by : technology nationalism, economic regionalism, market protectionism, multinational corporations, efc. All nations are striving for intensifying national economic rivalry and seeking after their own interests above everything else. Many regions of the world are also forming trading blocs, which could negatively affect nonmember states. The ultimate way to meet these difficulties is to establish production facilities in the countries imposing trade regulations. However, as the existing models of direct forrign investment (DFI) do not account for the particular nature of Korean firm's DFI activities, a new point of departure is imperative. It is because of this that Korean firms have only limited firm-specific advantages, the basic precondition of extant DFI theories, compared with their developed counterparts.

• Journal of Chest Surgery
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• v.31 no.4
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• pp.353-361
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• 1998

Hypothermia is widely acknowledged as fundamental component of myocardial protection during cardiac operations. Although it prolongs the period of ischemic arrest by reducing oxygen demands, hypothermia is associated with a number of major disadvantages, including its detrimental effects on enzymatic function, energy generation, and cellular integrity. The ideal way to rotect the heart is to electromechanically arrest it and perfus it with blood that is aerobic arrest. However alternative technique has been developed, based on the principles of electromechanical arrest and normothermic aerobic perfusion using continuous warm blood cardioplegia. To determine if continuous warm blood cardioplegia was beneficial in clinical practice during valvular surgery, we studied two groups of patients matched by numbers and clinical characteristics. Group included is 31 patients undergoing valvular surgery who received intermittent cold crystalloid cardioplegia. Group II included 30 patients undergoing valvular surgery who received continuous warm blood cardioplegia. Our results suggest that the heartbeat in 100% of patients treated with continuous warm blood cardioplegia converted to normal sinus rhythm spontaneously after the removal of the aortic cross-clamp, compared to only 31% of the cold cardioplegia group. After operation, pericardial closure rate was 90% area in the warm group, compared to 35% area in the cold group. 12 hours after the operation, the total amount of urine output in the warm group was greater than that in the cold group(2863${\pm}$127 ml versus 2257${\pm}$127 ml; p<0.05). After the operation, left diaphragmatic elevation developed in 55% of the cold group but in 0% of the warm group. CK-MB level in the warm group was significantly lower than cold group(2.28${\pm}$0.62 versus 9.96${\pm}$2.12; p<0.01) 1 hour after operation and CK-MB level in the warm group was significantly lower than cold group(1.80${\pm}$1.01 versus 6.00${\pm}$1.74; p<0.05) 12hours after operation. Continuous warm blood cardioplegia is at least as safe and effective as hypothermic technique in patients undergoing cardiac valvular surgery. Conceptually, this represents a new approach to the problem of maintaining myocardial preservation during cardiac operations.

• The Korean Society of Law and Medicine
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• v.13 no.1
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• pp.199-247
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• 2012

According to the review and analysis of medical cases that are assigned to the Supreme Court and all local High Court in 2011 and that are presented in the media, it was found that the following categories were taken seriously, medical and pharmaceutical product liability, the third principle of trust between medical institutions, negligence and causation estimation, responsibility limit, the meaning of medical records and related judgment of disturbed substantiation, Oriental doctors' duties to explain the procedures, IMS events, whether one can claim for each medical care operated by non-physician health care institutions to the nonmedical domain in the National Health Insurance Corporation, and the basis of norms for each claim. In the cases related to medical pharmaceutical product liability, Supreme Court alleviated burden of proof for accidents with medical and pharmaceutical products prior to the practice of Product Liability Law and onset the point of negative prescription as the time of damage strikes to condition feasibility of the specific situation. In the cases related to the 3rd principle of trust between medical institutions, the Supreme Court refused to sentence the doctor who has trusted the judgment of the same third-party doctors the violations of the care duty. With respect to proof of a causal relationship and damages in a medical negligence case, the Supreme Court decided that it is unjust to deny negligence by the materials of causal relationship rejecting the original verdict and clarified that the causal relationship shall not deny the reasons to limit doctors' responsibilities. In order not put burden on patients with disadvantages in which medical records and the description of the practice or the most fundamental and important evidence to prove negligence and causation are being neglected, the Supreme Court admitted in the hospital's responsibility for the case of the neonate death of suffocation without properly listed fetal heart rate and uterine contraction monitor. On the other hand, the Seoul Western District Court has admitted alimony for altering and forging medical records. With respect to doctors' obligations to description, the Supreme Court decided that it is necessary to explain the foreseen risks by the combination of oriental and western medicines emphasizing the right of patient's self-determination. However, questions have arisen whether it is realistically feasible or not. In a case of an unlicensed doctor performing intramuscular stimulation treatment (IMS), the Supreme Court put off its decision if it was an unlicensed medical practice as to put limitation of eastern and western medical practices, but it declared that IMS practice was an acupuncture treatment therefore the plaintiff's conduct being an illegal act. In the future, clear judgment on this matter should be made. With respect to the claim of bills from non-physical health care institutions, the Supreme Court decided to void it for the implementation of the arrangement is contrary to the commitments made in the medical law and therefore, it is invalid to claim. In addition, contrast to the private healthcare professionals, who are subject to redemption according to the National Healthcare Insurance Law, the Seoul High Court explicitly confirmed that the non-professionals who receive the tort operating profit must return the unjust enrichment and have the liability for damages. As mentioned above, a relatively wide range of topics were discussed in medical field of 2011. In Korea's health care environment undergoing complex changes day by day, it is expected to see more diverse and in-depth discussions striding out to the development in the field of health care.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.9
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• pp.637-648
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• 2009

As the cost of disks decreases, PCs are soon expected to be equipped with a disk of 1TB or more. Assuming that a single person generates 1GB of data per month, 1TB is enough to store data for the entire lifetime of a person. This has lead to the growth of researches on lifelog management, which manages what people see and listen to in everyday life. Although many different lifelog management systems have been proposed, including those based on the relational data model, based on ontology, and based on file systems, they have all advantages and disadvantages: Those based on the relational data model provide good query processing performance but they do not support complex queries properly; Those based on ontology handle more complex queries but their performances are not satisfactory: Those based on file systems support only keyword queries. Moreover, these systems are lack of support for lifelog group management and do not provide a convenient user interface for modifying and adding tags (metadata) to lifelogs for effective lifelog search. To address these problems, we propose a lifelog management system based on the relational data model. The proposed system models lifelogs by using the relational data model and transforms queries on lifelogs into SQL statements, which results in good query processing performance. It also supports a simplified relationship query that finds a lifelog based on other lifelogs directly related to it, to overcome the disadvantage of not supporting complex queries properly. In addition, the proposed system supports for the management of lifelog groups by providing ways to create, edit, search, play, and share them. Finally, it is equipped with a tagging tool that helps the user to modify and add tags conveniently through the ion of various tags. This paper describes the design and implementation of the proposed system and its various applications.

• Journal of Legislation Research
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• no.44
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• pp.611-653
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• 2013

An whistle-blowing is recognition of acts of misconduct or corruption by individuals(laborers) or party which belongs to a certain organization and it refers to the act of informing to the senior organization or to the outside public agency to avoid jeopardies that could be potentially lead against benefit of the public. These whistle-blowings can be a Ansatz that improve corporation's transparency and accountability by prevention of enterprise's misconduct as well, it has been recognized as an important role for the establishment of corporate ethics, moreover, social justice. What to be treated primarily as labor law problem is arousing some controversies of the possibility that the public announcement could be whether a disciplinary punishment or not because it brings some mischievous effects for the honor and the reputation to the company which conducted the illegal actions and the action of the contrary to the social value. And futhermore, recently, the matter of compensational responsibility according to the arrangement conversion, bullying followed by the informant has been brought up. The fundamental standpoint of precedent related with the judgement of justification for the punishment as reason of the whistle-blowing ought to do the sincere duty for the labor contract which is the employees are supposed to consider the employer's profits. For that reason, if the emploee release the inside fact to the public and give any damages to employer's secret or confidence or honor, it will be a causing reasong of the disciplinary punishment, but in specific cases, the relevant and level of punishment limitation can be judged by the contents of public announcement and the truth, the purpose of the acts and details and the way of announcement. Precisely, on the assumption that there are necessity of the characteristic profit or the freedom of expression for the informant, with overall consideration whether or the basis part of the informant is true or there is a fair reason which make the informant believe is true or the purpose of informant has the public profit or the contents of the whistle-blowing are important for relevant organization or the means and the way was suitable, if the whistle-blowing are approved to be resonable, the organization are not permitted the reprimand or dismiss Futhermore, to find the solution for the issues of the disciplinary punishment and the treatment of all sorts of disadvantages, for the reason of whistle-blowing, since the protection law for public declarer which was enacted in last 2011 have the position as the general law, the purport of the equal law has to be considered sytematically and also the judicial precedent which is related to the justification of whistle-blowing are needed to be considered as well.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.376-387
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• 2019

Melons are mostly grown in soil, but it is susceptible to damage due to injury by continuous cropping such as Fusarium wilt and root rot. Hydroponic cultivation system can overcome the disadvantages of soil cultivation with precise nutrition management and a clean environment. When using the coir substrate, the most environmentally friendly organic substrate used for hydroponics, it is analyzed how the growth and fruit quality of the melon depends on the ratio of chips and dust and the amount of irrigation. The purpose of this study was to provide the basic data of melon hydroponics when cultivated in spring. The two types of the coir substrates used in the experiments were chip and dust ratios of 3 :7 and 5 : 5 respectively. The substrate with high dust ratios had excellent physical characteristics, such as container capacity and total porosity, and the drainage EC level showed a high value of $3.0-6.8dS{\cdot}m^{-1}$. When the amount of irrigation is provided based on the drainage rate, the group provided the nutrient solution on the basis of 10% drainage supplied 91 L per plant, which was reduced by about 30% compared to the group with the highest water supply. In addition, the total drainage showed less than 10 L per plant with a minimum water supply and was reduced by 30 - 70% in substrate with a high dust rates. In substrate with high water supply and high dust ratio, leaf growth and fruit enlargement were good, and the soluble solids content varies greatly from cultivar to cultivar. If you provided the amount of irrigation based on 10% drainage rate, the fruit weight will be decreased, but the amount of irrigation can be reduced. Therefore, it is considered that managing the water & nutrient properly taking into account the characteristics of coir substrate and cultivar can produce melon of uniform quality using hydroponics.

• Clean Technology
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• v.27 no.4
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• pp.341-349
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• 2021

In combustion facilities, the nitrogen and sulfur in fossil fuels react with oxygen to generate air pollutants such as nitrogen oxides (NO_X) and sulfur oxides (SO_X), which are harmful to the human body and cause environmental pollution. There are regulations worldwide to reduce NO_X and SO_X, and various technologies are being applied to meet these regulations. There are commercialized methods to reduce NO_X and SO_X emissions such as selective catalytic reduction (SCR), selective non-catalytic reduction (SNCR) and wet flue gas desulfurization (WFGD), but due to the disadvantages of these methods, many studies have been conducted to simultaneously remove NO_X and SO_X. However, even in the NO_X and SO_X simultaneous removal methods, there are problems with wastewater generation due to oxidants and absorbents, costs incurred due to the use of catalysts and electrolysis to activate specific oxidants, and the harmfulness of gas oxidants themselves. Therefore, in this research, microbubbles generated in a high-pressure disperser and reducing agents were used to reduce costs and facilitate wastewater treatment in order to compensate for the shortcomings of the NO_X, SO_X simultaneous treatment method. It was confirmed through image processing and ESR (electron spin resonance) analysis that the disperser generates real microbubbles. NO_X and SO_X removal tests according to temperature were also conducted using only microbubbles. In addition, the removal efficiencies of NO_X and SO_X are about 75% and 99% using a reducing agent and microbubbles to reduce wastewater. When a small amount of oxidizing agent was added to this microbubble system, both NO_X and SO_X removal rates achieved 99% or more. Based on these findings, it is expected that this suggested method will contribute to solving the cost and environmental problems associated with the wet oxidation removal method.

• The Korean Journal of Archival Studies
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• no.16
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• pp.97-146
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• 2007

Those days when people used paper to make up and manage all kinds of documents in the process of their jobs are gone now. Today electronic types of documents have replaced paper. Unlike paper documents, electronic ones contribute to the maximum job efficiency with their convenience in production and storage. But they too have some disadvantages; it's difficult to distinguish originals and copies like paper documents; it's not easy to examine if there is a change or damage to the documents; they are also prone to alteration and damage by the external influences in the electronic environment; and electronic documents require enormous amounts of workforce and costs for immediate measures to be taken according to the changes to the S/W and H/W environment. Despite all those weaknesses, however, electronic documents increasingly account for more percentage in the current job environment thanks to their job convenience and efficiency of production costs. Both the government and private sector have made efforts to come up with plans to maximize their advantages and minimize their risks at the same time. One of the methods is the Authorized Retention Center which is described in the study. There are a couple of prerequisites for its smooth operation; they should guarantee the legal validity of electronic documents in the administrative aspects and first secure the reliability and authenticity of electronic documents in the technological aspects. Responding to those needs, the Ministry of Commerce, Industry and Energy and the Korea Institute for Electronic Commerce, which were the two main bodies to drive the Authorized Retention Center project, revised the Electronic Commerce Act and supplemented the provisions to guarantee the legal validity of electronic documents in 2005 and conducted researches on the ways to preserve electronic documents for a long term and secure their reliability, which had been demanded by the users of the center, in 2006. In an attempt to fulfill those goals of the Authorized Retention Center, this study researched technical standard for electronic record information package of the center and applied the ISO 14721 information package model that's the standard for the long-term preservation of digital data. It also suggested a process to produce and manage information package so that there would be the SIP, AIP and DIP metadata features for the production, preservation, and utilization by users points of electronic documents and they could be implemented according to the center's policies. Based on the previous study, the study introduced the flow charts among the production and progress process, application methods and packages of technical standard for electronic record information package at the center and suggested some issues that should be consistently researched in the field of records management based on the results.

• Journal of the Korean GEO-environmental Society
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• v.20 no.2
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• pp.41-48
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• 2019

Soil compaction is one of the most important activities in the area of civil works, including road construction, airport construction, port construction and backfilling construction of structures. Soil compaction, particularly in road construction, can be categorized into subgrade compaction and roadbed compaction, and is significant work that when done poorly can serve as a factor causing poor construction due to a lack of compaction. Currently, there are many different types of compaction tests, and the plate bearing test and the unit weight of soil test based on the sand cone method are commonly used to measure the degree of compaction, but many other methods are under development as it is difficult to secure economic efficiency. For the purpose of this research, a portable penetration meter called the Free-Fall Penetration Test (FFPT) was developed and manufactured. In this study, a homogeneous sample was obtained from the construction site and soil was classified through a sieve analysis test in order to perform grain size analysis and a specific gravity test for an indoor test. The principle of FFPT is that the penetration needle installed at the tip of an object put into free fall using gravity is used to measure the depth of penetration into the road surface after subgrade or roadbed compaction has been completed; the degree of compaction is obtained through the unit weight of soil test according to the sand cone method and the relationship between the degree of compaction and the depth of the penetration needle is verified. The maximum allowable grain size of soil is 2.36 mm. For $A_1$ compaction, a trend line was developed using the result of the test performed from a drop height of 10 cm, and coefficient of determination of the trend line was $R^2=0.8677$, while for $D_2$ compaction, coefficient of determination of the trend line was $R^2=0.9815$ when testing at a drop height of 20 cm. Free fall test was carried out with the drop height adjusted from 10 cm to 50 cm at increments of 10 cm. This study intends to compare and analyze the correlation between the degree of compaction obtained from the unit weight of soil test based on the sand cone method and the depth of penetration of the penetration needle obtained from the FFPT meter. As such, it is expected that a portable penetration tester will make it easy to test the degree of compaction at many construction sites, and will lead to a reduction in time, equipment, and manpower which are the disadvantages of the current degree of compaction test, ultimately contributing to accurate and simple measurements of the degree of compaction as well as greater economic feasibility.