• Journal of the Korea Society of Computer and Information
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• v.15 no.4
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• pp.91-98
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• 2010

Advances in communications and control technology, the strengthening of the Internet, and the growing recognition of the urgency to reduce the risk and production cost are motivating the development of improvements in the traditional manufacturing industry. In this paper, we developed a remote dust collector bag control system which is a combination of advanced IT and traditional dust collector based on the event. At first, we made the A/D(Analog/Digital) converter using a micro processor because the differential pressure transmission, which is a sensor of the dust collector, produces analog volt data. A/D converter can provide RS-232 communication to connect with Power Line Communication(PLC) modem. And, n-bytes message format was defined for the efficient dust collector bag information transmission from a dust collector to a user. Also, we designed the data types to model the dust collector and the dust collector bag, and they were logically modeled using XML and object-oriented modeling method. In addition to that, we implemented the system for showing the dust collector bag exchange time exactly to users at real-time using various visual user interfaces.

• 수도
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• v.24 no.5 s.86
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• pp.29-44
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• 1997

Sewage sludge produced in Korea was 1,275,800 tons (dewatered sludge cake) per year in 1996, which is 3,495 tons per day, 0.303% of 11,526,100 tons per day of sewage treated in 79 sewage treatment plants. Sludge production has been and will be increasing in accordance with construction of new facilities for sewage treatment. Most of the sludge is currently disposed by landfill and ocean dumping, but it is becoming difficult to find suitable sites for landfill, particularly in big cities such as Seoul. In addition, rapid increase of landfill cost is anticipated in a near future. Current trend for sludge disposal in advanced countries is land application. Over the past 10 to 20 years in the United States, sludge management practices have changed significantly, moving from disposal to beneficial use. They use biosolid for utilization instead of sludge for disposal. Under the Clean Water Act of 1972, amended in 1987 by Congress, the U.S. EPA was required to develop regulations for the use and disposal of sewage sludge. The EPA assessed the potential for pollutants in sewage sludge to affect public health and the environment through a number of different routes of exposure. The Agency also assessed the potential risk to human health through contamination of drinking water sources or surface water when sludge is disposed on land. The Final Rules were signed by the EPA Administrator and were published (Federal Register, 1993). These rules state that sewage sludge shall not be applied to land if the concentration of any pollutant in the sludge exceeds the ceiling concentration. In addition, the cumulative loading rate for each pollutant shall not exceed the cumulative pollutant loading rate nor should the concentration of each pollutant in the sludge exceed the monthly average concentration for the pollutant. The annual pollutant loading rate generally applies to applications of sewage sludge on agricultural lands. The most popular beneficial use of sewage sludge is land application. The sludge has to be stabilized for appling to land. One of the stabilization process for sewage sludge is lime stabilization process. The stabilization process is consisted of the stabilizing process and the drying process. Stabilization reactor can be a drum type reactor in which a crossed mixer is equipped. The additive agents are a very reactive mixture of calcium oxide and others. The stabilized sludge is dried in sun drier or rotary kiln.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.47
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• pp.129-156
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• 2010

Since the 1970s, international construction employers have commonly requested first demand guarantees upon their contractors as a form of security for due performance of their works. Contractors prefer the greater protection offered by more traditional forms of security requiring presentation of an arbitral award or other evidence of the caller's entitlement to compensation. Many contractors nonetheless feel that they have no alternative but to provide these unconditional guarantees in order to compete. However, these unconditional first demand guarantees are controversial and have given rise to numerous disputes both in arbitration and litigation. Disputes arising from first demand guarantees can be broken down into a) applications to prevent a perceived fraudulent or otherwise unfair or improper calling of a guarantee, b) claims arising from such abusive calls and c) claims relating to the consequences of such calls even if the call itself may not be abusive as such. The contractors should carefully assess the risk of an abusive call being made bearing in mind the difficulties he may face in seeking to prevent such a call. He should also bear in mind the difficulties, delays and cost he is likely to encounter in seeking to recover any monies wrongfully called. One option would be to provide that the call can only be made once and to the extent that the employer's damages have been assessed or even incurred or even for the default to have been established by an arbitral tribunal or court. Another option would be to provide that any call be accompanied by a decision of a competent and impartial third party stating that the contractor is in breach. For example, such a requirement could be incorporated into a construction contract based on the FIDIC Conditions by submitting this decision to a Dispute Adjudication Board. Another option would be to provide for the "ICC Counter-Guarantee Scheme". In sum, there would appear to be room for compromise between the employer and the contractor in respect of first demand guarantees by conditioning the entitlement to call such guarantees to the determination of a competent and impartial third party.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.1 no.2
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• pp.117-121
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• 2008

Prolotherapy can be defined as the injection of growth factors or growth factor production stimulants to grow normal cells or tissue. Even though it has been a controversal procedure for decades, it is currently gaining in popularity among many physicians. The term prolotherapy was coined by Hacket in the 1950s to imply proliferation of normal tissue at ligamentous and tendinous entheses. The procedure has been described by other terms, such as sclerotherapy, regenerative injection therapy, and stimulated ligament repair. Incomplete healing from sprains or strains is common and can lead to chronic pain, joint instability and laxity, and is a risk factor for the development of osteoarthritis. Prolotherapy is commonly used for these musculoskeletal conditions which are refractory to usual care therapies. The proliferant solution and technique varies according to physicial training and preferance. Commonly reported proliferants include 10% to 25% dextrose, P2G and sodium morrhuate. High resolution ultrasound imaging of musculoskeletal tissue is increasing in popularity because of patient tolerability, low cost, ability to visualize tissue in real time motion and superior resolution of highly organized tissue such as a tendon. This procedure can be introduced by ultrasound imaging and tissue growth and repair after this procedure in a tendon or a ligament can be documented with ultrasound.

• The Journal of Fisheries Business Administration
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• v.25 no.2
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• pp.115-145
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• 1994

The objetives of this study are to find the economic feasibility of the polyculture and to give the economic information of the polyculture for aquaculture fishermen. The polyculture is defined as the rearing of several species together to make more efficient use of the growing space and the total ground environment. The economic feasibility analysis in the polyculture involves the profitability, the productivity, and the risk reduction effect. The results of the economic feasibility analysis in the polyculture are as follows; First, in the profitability analysis, the solid utilization of ground in the polyculture is more profitable than the monoculture. The profitability owing to the plane utilization of the ground in the polyculture is positioned between those of the monoculture of each speices. Second, in the productivity analysis, oyster and sea squirt are diminishing returns to scale. Third, the variation on the average rate of return in the polyculture products is smaller than that of the monoculture. Finally, the result of comparison between the polyculture and the monoculture shows that the polyculture in coastal area is more profitable and more efficient than the monoculture. Most of cultivating species are selective in their diet Thus, stocking different kinds of cultivating species will efficiently utilize space and food It seems that polyculture is more appropriate for those species that live in different ecological niches. We think that the production per unit of ground can be increased, and the fixed cost per unit of output be reduced, so the polyculture is more profitable than the monoculture. Based on the above results, we concludes that the polyculture is economically feasible when profitability and productivity are increased and simultaneously the variation of average rate of return in the polyculture is smaller than that of the monoculture.

• The Journal of Fisheries Business Administration
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• v.33 no.2
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• pp.1-29
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• 2002

The main objective of this research aims at analyzing efficiency of government financial transfers(GFTs) to the Korean fisheries sector, using the Linear Structural Relations model(i.e., LISERL model) and the field survey data. Most policies of GFTs tend to be implemented to protect industries with weak competitive advantages such as infant and/or primary industries. Specific policy instruments include income transfers, government loans with lower interest rates, taxes and the like. Fishing activities are made at a highly changeable natural environment of the ocean with a great amount of risk and uncertainty. Fishing households make their livelihood under the small-scale fisheries. Such fisheries and fishing households have also a relatively weak market power. Because of these fisheries characteristics most coastal states have adopted a variety of government support programs. However, despite such a huge government support, during the past several decades the world fishing communities have seen a tendency of continuous fishereis resource overexploitation. For this resason there have been hot debates over the government support policies for fisheries through OECD, FAO, WTO, and UNEP. In general, policy evaluations tend to be made on the basis of benefit-cost(B/C) analysis. However, the B/C analysis may produce results quite different from real ones primarily due to many unmeasurable effects. Thus, the authors composed simple questionaires and let fishermen, government officials and academic people answer the questions. The survery was made in several ways such as post-mail and personal/group interviews. In recent years, for analysis of policy performances and effectiveness, the LISREL model has often been used, which consists of structural and measurement eqquations. This model has a good advantage of transforming unobservable variables to observable ones so that it helps construct endogenous cause and effect relationships among relevant variables. The evaluation was done from the two aspects: policy results and policy effectiveness. The policy result evaluation showed that there is a need for improvement for policy problem perception and decision-making process, while the policy effect evaluation suggested that the policy goals were successfully achieved and social justice was improved from the perspective of the entire society as well. However, the research results showed that the GFT policies rendered little contrubtion to narrowing down the gap between GFT beneficiaries and non-beneficiaries incomes.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.3
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• pp.301-306
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• 2008

Drivers are becoming more fatigued and uncomfortable with increase in traffic density, and this condition can lead to slower reaction time. Consequently, they may face the danger of traffic accidents due to their inability to cope with frequent gear shifting. To reduce this risk, some drivers prefer automatic transmission (AT) over manual transmission (MT). The AT offers more superior drivability and less shifting shock than the MT; therefore, the AT market share has been increasing. The AT is controlled by an electronic control unit (ECU), which provides better shifting performance. The transmission control unit (TCU) is a higher-value-added product, so the companies that have advanced technologies end to evade technology transfer. With more cars gradually using the ECU, the TCU is expected to be faster and more efficient for organic communication and arithmetic processing between the control systems than the l6-bit controller. In this paper, the model of an automatic transmission vehicle using MATLAB/Simulink is developed for the Hardware in-the-Loop (HIL) simulation with a 32-bit embedded system, and also the AT control logic for shifting is developed by using MATLAB/Simulink. The developed AT control logic, transformed automatically by real time workshop toolbox, is loaded to a 32-bit embedded system platform based on Freescale's MPC565. With both vehicle model and 32-bit embedded system platform, we make the HIL simulation system and HIL simulation of AT based on real time operating system (RTOS) is performed. According to the simulation results, the developed HIL simulator will be used for the performance test of embedded system for AT with low cost and effort.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.4
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• pp.73-78
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• 2018

In this paper, we consider a system where multiple sources are encrypted in separated nodes and sent through their respective public communication channels into a joint sink node. We are interested at the problem on protecting the security of an already existing system such above, which is found out to have correlated encryption keys. In particular, we focus on finding a solution without introducing additional secret keys and with minimal modification to minimize the cost and the risk of bringing down an already running system. We propose a solution under a security model where an eavesdropper obtains all ciphertexts, i.e., encrypted sources, by accessing available public communication channels. Our main technique is to use encoders of universal function to encode the ciphertexts before sending them to public communication channels.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.6
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• pp.1937-1944
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• 2014

In recent years, common ducts have been installed and operated in the sidewalls of tunnels to prepare for emergencies in tunnel construction and maintenance. The installation of common ducts is done mainly by humans. Problems with cost increases are inherent in tunnel construction by humans due to the safety risks and the economic inefficiency of humans performing construction activities. Among the problems that arise are poor illumination due to the use of temporarily installed electricity, the risk of accidents due to the confined workspaces, and workers avoiding work tasks because of the poor environment in tunnel. Ideas for solving these problems were developed using a value engineering (VE) process, and mechanized construction was identified as a promising solution. To verify the effectiveness of mechanized construction of a common duct in tunnels, experimental construction work was carried out, and mechanized construction was proven to directly improve the constructability and economic efficiency of common duct construction. In addition, reducing human involvement in common duct construction in tunnels is expected to improve safety, and because of the continuous concrete placement technique used, the finish and appearance of the ductwork are improved.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.3
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• pp.493-498
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• 1998

Computed tomography(CT) has become more widely available in recent years and is recognized as an important diagnostic tool for complex disease and condition of the orofacial structure in adults. In pediatric patients, especially in the mixed dentition period, the number of superimposing dental structures in the jaw bone is much greater than in the permanant dentition period. Therefore, in spite of radiation risk, computed tomography should sometimes be used in pediatric patients in order to obtain a precise and valid diagnosis. This case study presents clinical application of computed tomography on patients visiting department of pediatric dentistry in Seoul National University Dental Hospital. The results obtained through these cases were summarized as follow : 1. Localization of impacted teeth using CT allows for efficient treatment planning leading to reduced postoperative complications. 2. In orthodontic traction of impacted permanent teeth, utilization of CT made exact localization of window site and determination of prognosis possible. 3. Use of CT made possible definite diagnosis of lesions in the jaw that were only suspected on plain film radiographs. 4. Careful selection is necessary when applying CT on children due to increased radiation dose and high cost.