• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.2
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• pp.156-165
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• 2014

This paper is the first investigation on the effect of flow control methods on the part load performance in a spark ignition engine. For comparison of the methods, two control devices, port throttling and masking, were applied to a conventional engine without any design change of the intake port. Steady flow evaluation shows that steady flow rates per unit opening area and swirl ratio are very low compared with the port throttling and saturated from mid-stage valve lift, however, swirl increases slightly as the lift is higher in case of 1/4 masking control. In the part load performance, the effect of simple port throttling on lean misfire limit expansion is limited and insufficient; on the other hand a masking improves the limit considerably without any port modification for increasing swirl. Also the results show that the intake flow control improves the combustion with following two mechanisms: stratification induced by the combination of the flow pattern and the fuel injection timing attribute to ignition ability and the intensified flow ensure fast burn. In addition fuel consumption reduces under the flow controls and the reduction rate is different according to the operation conditions and control methods. At the Stoichiometric and/or low speed and low load the throttling method is more advantageous; however vice versa at lean and high load condition. Finally, the throttling is more efficient for HC reduction than masking, on the other side the NOx emissions increase under the masking and decrease under the port throttling compared with conventional port scheme.

• Journal of Korean Society on Water Environment
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• v.30 no.5
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• pp.491-502
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• 2014

As meteorology is the driving force for lake thermodynamics and mixing processes, the effects of climate change on the physical limnology and associated ecosystem are emerging issues. The potential impacts of climate change on the physical features of a reservoir include the heat budget and thermodynamic balance across the air-water interface, formation and stability of the thermal stratification, and the timing of turn over. In addition, the changed physical processes may result in alteration of materials and energy flow because the biogeochemical processes of a stratified waterbody is strongly associated with the thermal stability. In this study, a novel modeling framework that consists of an artificial neural network (ANN), a watershed model (SWAT), a reservoir operation model(HEC-ResSim) and a hydrodynamic and water quality model (CE-QUAL-W2) is developed for projecting the effects of climate change on the reservoir water temperature and thermal stability. The results showed that increasing air temperature will cause higher epilimnion temperatures, earlier and more persistent thermal stratification, and increased thermal stability in the future. The Schmidt stability index used to evaluate the stratification strength showed tendency to increase, implying that the climate change may have considerable impacts on the water quality and ecosystem through changing the vertical mixing characteristics of the reservoir.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.5
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• pp.147-156
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• 2008

As the management of fuel efficiency becomes globally reinforced in attempts to find an environment-friendly vehicle that will operate against global warming, the interest in and the demand for the type of vehicle with a high-efficiency diesel engine using light oil. However, it also emits a greater amount of PM (particulate matter) and NOx than emissions from vehicles using other types of fuels. Therefore, the DME (Dimethyl Ether), an oxygen containing fuel draws attention as an alternative fuel for light oil that can be used for diesel engines since it generates very little smoke. But to develop and compare performance of an electric controlled common-rail DME engine, engine tests requires optimized injection conditions at required engine RPM and engine torque. These injection conditions cannot be set freely and the data configuration through the experimentally repeated application requires much time as well as a significant amount of errors and effort. The object of this study is to configure the basic injection map using the results of the DME engine experiments performed so far. For this, in this study, the functionalization of the required equations were performed along with the basic review of the factors that had influence on the data map. Through this, the information on the injection pressure, injection amount, injection duration, injection timing, etc. under certain operation condition could be obtained.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.7
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• pp.98-105
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• 2005

In this paper, the decryption function of CCSDS telecommand of CTU EQM for the security of communications satellite was verified. In order to intensify the security level of DES CFB decryption algorithm applied to CTU EM, 3DES CFB decryption algorithm using three keys is implemented in the CTU EQM. As the decryption keys increased due to the 3DES algorithm, the keys and IV are stored in PROM memory, and used for the telecommand decryption by taking the keys and IVs corresponding to the selected key and IV indexes from the memory. The operation of the 3DES CFB is validated through the timing simulation of 3DES CFB algorithm, and then the 3DES CFB core implemented on the A54SX32 FPGA. The test environment for the telecommand decryption verification of the CTU EQM was built up. Through sending and decrypting the encrypted command, monitoring the opcodes, and confirming LED on/off by executing the opcodes, the 3DES CFB telecommand decryption function of the CTU EQM is verified.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.39 no.6
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• pp.257-262
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• 2013

Objectives: Oral and maxillofacial defects often require bone grafts to restore missing tissues. Well-recognized donor sites include the anterior and posterior iliac crest, rib, and intercalvarial diploic bone. The proximal tibia has also been explored as an alternative donor site. The use of the tibia for bone graft has many benefits, such as procedural ease, adequate volume of cancellous and cortical bone, and minimal complications. Although patients rarely complain of pain, swelling, discomfort, or dysfunction, such as gait disturbance, both patients and surgeons should pay close attention to such after effects due to the possibility of tibial fracture. The purpose of this study is to analyze tibial fractures that occurring after osteotomy for a medioproximal tibial graft. Materials and Methods: An analysis was intended for patients who underwent medioproximal tibial graft between March 2004 and December 2011 in Inha University Hospital. A total of 105 subjects, 30 females and 75 males, ranged in age from 17 to 78 years. We investigated the age, weight, circumstance, and graft timing in relation to tibial fracture. Results: Tibial fractures occurred in four of 105 patients. There were no significant differences in graft region, shape, or scale between the fractured and non-fractured patients. Conclusion: Patients who undergo tibial grafts must be careful of excessive external force after the operation.

• Informatization Policy
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• v.19 no.2
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• pp.85-105
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• 2012

So far, the importance of informatization, as well as investment into it, has been growing steadily. Due to the uncertainties and risks in adopting information technologies, systematic decision-making is definitely needed in investing in a large scale information system. Based on the existing theories about the economic life span of information systems and in consideration of the actual cost involved in the adoption and operation of the systems by the financial institutions in Korea, this study presents the optimal economic life span for all types of information systems in terms of the economic cost and generalizes the optimal life span. The ultimate purpose of this study is to develop a model that could be used in anticipating the timing of economic replacement of the information system of the same type and making decisions on IT investment.

• Korean Journal of Cleft Lip And Palate
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• v.8 no.2
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• pp.87-94
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• 2005

Patients with unilateral cleft lip and palate (UCLP) generally demonstrate the asymmetries in the lip, nose and the naso-maxillary complex. And their skeletal asymmetries are known to be derived from the displacement of nasal septum, anterior nasal spine (ANS) and the pre-maxilla toward the non-affected side during the developmental and growth period. Due to the interruption of the important facial muscles, which are critical for the symmetric growth of premaxilla, functional matrix system fails to develop and results in the displacement of the ANS toward the non-affected side and nasal asymmetry. Therefore the rhinoplasty for CLP patients is required to have inter-skeletal and muscular rearrangement in the naso-maxillary complex in order to let them recover from esthetic and physiologic imbalances. And functional cheilorhinoplasty (FCR) has been a representative treatment of choice for this concept of treatment modality. The outcome and prognosis of primary or repair FCR have been known to be definitely affected by timing of the operation as well as adequate reconstruction of naso-labial muscles. However, sometimes FCR has an ineffective treatment results for patients after the facial growth period, and the limited rhinoplasty around the nose often fails to bring satisfying results. In order to circumvent this limitation, we performed ANS osteotomy for patients with unilateral CLP showing asymmetric nose, as an alternative way for corrective rhinoplasty. We could observe that the nose was rearranged along the facial mid-line by this osteotomy design and asymmetries were evidently improved postoperatively. Here we present this osteotomy method in CLP patients.

• The Journal of Korean Medicine
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• v.33 no.4
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• pp.69-80
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• 2012

Objectives: The purpose of this study is to develop a clinical practice observation course in a medical school that can give Korean medical students opportunities to experience the treatment environment in western medicine, and to analyze the results of the course. Methods: A total of 47 (collection rate: 85.5%) senior students of the College of Korean medicine in Gyunggi-do replied to the survey. Twenty-seven of them were male and 20 were female. They participated in the clinical practice observation course in the medical school two days a week for two weeks (total: four days) in the academic year 2011-2012. Before the course, an orientation was held; and upon the students' completion of the course, they presented their experiences and replied to the survey. Results: According to the survey, the purpose of the course was well explained (91.5%), and the course was necessary for Korean medical students (97.9%). The four-day course duration was inappropriate, though (83%). The female students were more satisfied with their participation in the fourth year and with the timing of the course than the male students were. The students who finished the course at the surgical departments recognized the necessity of the course more than the students who finished the course at the non-surgical departments. The advantages of the course included opportunities to observe operation scenes and experience clinical treatment processes and systems. The weakness of the course included poor organization due to the short preparation period. Conclusions: The course was confirmed as necessary for Korean medical students so that they would understand the treatment environment in western medicine. Through the course, the students broadened the understanding of the disease and developed a strong sense of identity as Korean medical students. The duration of the course needs to be extended, and its structure should be enhanced. Furthermore, various educational programs that offer Korean medical students opportunities to experience various clinical cases need to be introduced.

• Cartoon and Animation Studies
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• s.41
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• pp.57-73
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• 2015

A pose is an important component in the animation with timing and spacing. Pose is the key to describe the story-telling or how the animation behavior. Key animation method is Straight Ahead and pose to pose method. Many animaters have been using these two methods, or by a mix of two ways. It is possible that computer animation make a pose using interpolation between keyframes. The many animators of computer animation are using pose to pose in their work. It is depend on good and strong pose that make audience understand a story or a situation. This makes animators to be efficient of inefficient operation. In this study, according to the effective good pose to catch proposes four ways. There are four methods of making pose that are stretch and squash, the height of the character, the center of weight, step. The law of 12 kinds of Disney Animation is a good reference for the study.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.9
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• pp.11-20
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• 1998

High-speed complex-number arithmetic units are essential to baseband signal processing of modern digital communication systems such as channel equalization, timing recovery, modulation and demodulation. In this paper, a new complex-number multiplication algorithm is proposed, which is based on redundant binary (RB) arithmetic combined with radix-4 Booth recoding scheme. The proposed algorithm reduces the number of partial product by one-half as compared with the conventional direct method using real-number multipliers and adders. It also leads to a highly parallel architecture and simplified circuit, resulting in high-speed operation and low power dissipation. To demonstrate the proposed algorithm, a prototype complex-number multiplier-accumulator (CMAC) core with 10-bit operands has been designed using 0.8-$\mu\textrm{m}$ N-Well CMOS technology. The designed CMAC core contains about 18,000 transistors on the area of about 1.60 ${\times}$ 1.93 $\textrm{mm}^2$. The functional and speed test results show that it can operate with 120-MHz clock at V$\sub$DD/=3.3-V, and its power consumption is given to about 63-mW.