• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.2 s.332
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• pp.61-74
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• 2005

Digital Multimedia Broadcasting(DMB) is a reliable multi-service system for reception by mobile and portable receivers. DMB system allows interference-free reception under the conditions of multipath propagation and transmission errors using COFDM modulation scheme, simultaneously, needs powerful channel error's correction ability. Viterbi Decoder for DMB receiver uses punctured convolutional code and needs lots of computations for real-time operation. So, it is desired to design a high speed and low-power hardware scheme for Viterbi decoder. This paper proposes a combined add-compare-select(ACS) and path metric normalization(PMN) unit for computation power. The proposed PMN architecture reduces the problem of the critical path by applying fixed value for selection algorithm due to the comparison tree which has a weak point from structure with the high-speed operation. The proposed ACS uses the decomposition and the pre-computation technique for reducing the complicated degree of the adder, the comparator and multiplexer. According to a simulation result, reduction of area $3.78\%$, power consumption $12.22\%$, maximum gate delay $23.80\%$ occurred from punctured viterbi decoder for DMB system.

• Journal of the Korean earth science society
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• v.39 no.3
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• pp.275-290
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• 2018

This study is to investigate how science and engineering integrated (SEI) lessons affect science-gifted students' perceptions about engineers and engineering practices. Twenty elementary science gifted students participate in this study, and they reflect what engineering practice means such as managing limited time and budget. The SEI lessons with 24 hours class time are used as an intervention. The main data are collected with 'engineer and engineering drawing test', open-ended questions and interviews about the drawing, and focus group interviews about the lessons. The transcribed interview data are analyzed using mixed methodology of quantitative (descriptive and paired t-test) and qualitative methods. The result shows that the SEI lessons have positive impacts on the science-gifted students' perceptions about engineers and engineering practices such as engineering design. After the lessons, the students perceive engineering and engineers in a desired way such as engineering as a social practice that many experts work collaboratively, the interaction between engineering and society, and the importance of ethics and social values in engineering practice.

• Journal of Navigation and Port Research
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• v.28 no.3
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• pp.269-276
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• 2004

The reclaimed land has peculiar characteristic of nature environment unlike midtown or inland and also, in comparison with inland, has bad weather condition, such as low temperature, strong wind, excessive sunshine, and moisture involved in a salt. Therefore the case of developing water front needs understanding characteristic of weather environment mused by reclamation in detail and proper development and organized maintenance. If development which doesn't investigate topographic and climate characteristic sufficiently is drove ahead, a rise of expense for energy and maintenance is going to be mused by deteriorating weather environmental, occurring a flaw of facility and calculating inaccurate capacity of facility. We looked into the weather state and drew up the standard weather data of the newport area in Busan which is reclaiming and developing now. In this research at the base qf the standard weather data, we calculate the dynamic peak loads for commerce, business and residence and then we utilize the results of the load calculation as basic information to determine facility capacity in the rear city of the newport area.

• Information Systems Review
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• v.9 no.2
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• pp.149-168
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• 2007

As the need for quantitative qualities of IT investment performance heightens, numerous research organizations are developing various measurement methods for the quantitative evaluation and its currency value conversion. Corporations utilizing these methods to evaluate IT investment performance are gradually increasing. However, working-level staff in the corporations that have introduced the quantitative evaluation can not assure if the evaluation sufficiently reflects the actual effect provided by IT since the results arising from the conversion of currency value can't be visibly confirmed. This study tries to identify whether the quantitative evaluation of IT investment performance can be explained in terms of the level of consumer satisfaction proven by the qualitative evaluation by analyzing the level of consumer satisfaction and quantitative evaluation of a case company and identifying the correlation between them. As the result of the case study, the following points have been concluded. Firstly, the currency value of IT effect correlates with the level of consumer satisfaction. Secondly, in order to come up with a rational currency value of IT effect, developing an indicator as well as managing data on currency conversion that will enable the internal system's efficiency to become more quantitative is essential. Thirdly, IT ROI is not appropriate to compare the performance between systems and is utilized as a measurement standard for each system's performance and efficiency. Lastly, quantitative evaluation is still inadequate in the evaluation of the system's strategic side, and consumer satisfaction can be utilized as a supplementary method.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.7
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• pp.754-759
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• 2015

Nowadays, short distance communication systems with low power energy (LPE) are developed for identification and monitoring of site identification of vessel crews and passengers (SIVCP). LPE communication modules, such as Bluetooth low energy (BLE) and Zigbee, are used for short distance communications with LPE. These modules enable 1:N communications and their popularity is growing since the modules can be mounted on movable objects, such as mobile devices and human body. When these modules are used, the important factor that affects their operation time and design are the capacity and size of battery. Therefore, they must be made as small as possible, and the battery should be selected to be slightly smaller than the module. In this study, we calculate the theoretical life of batteries used in SIVCP BLE modules using data sheet and discharge characteristic graph under the condition of a 1/250 transmission-ratio (TR). We thus calculate experimental life by measuring transmission current for the same TR, and low speed mode current for a 1/5000 TR and measure long-term experimental life using 1/25 TR for days. Through these experiments, we verify experimental methods for the prediction and extension of battery life that would enable us to select appropriate sizes of batteries based on vessel usage and passenger types. The selections of the module TR and battery size are important factors affecting the cost reduction of module design, the battery maintenance, and passenger convenience.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.794-805
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• 2017

This paper proposes a Hardware-In-Loop(HIL) Simulator for a Wind Turbine and an operational control algorithm to evaluate the performance of a wind turbine control system. It provides not only for the validation of the control logics, safety functions and H/W failure, but also for the high reliability of the wind turbines (by reducing/and the reduction of the operating expense(OPEX) through performance evaluation tests with complex scenarios. On the other hand, the proposed simulator uses MATLAB, CODER, and the PLC library to operate in synchronization with the hardware, and a real-time processing-based wind turbine module including a dynamic model and control system, wind module, grid module and host PC to manage the HIL-simulator. Several experiments were carried out under the above concept to verify the effectiveness of the proposed WT HIL-simulator.

• Journal of the Korea Institute of Building Construction
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• v.13 no.2
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• pp.181-192
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• 2013

Given both structural safety and economic benefits of aging facilities, remodelling of the existing facilities is preferable to reconstruction. This recognition provides an opportunity to reduce the commitment of resources and national budget. However, when a subordinate troop asks for remodeling or reconstruction of a deteriorated facility, it is difficult to ensure the consistency and objectivity in the process of decision making for the alternatives due to the absence of systematic and quantitative rating methodology. Their economic evaluation methodology only exists in a manual format. Thus, further research is required for converting the methodology into an automated system in view of practicality such as rapid and accurate data processing. The contributions of this study are as follows: 1) Literature review found out a representative economic evaluation model focused on military facilities, and comparative analysis with a similar study identified the strength and weakness. 2) this study presented how to convert the theoretical framework which enables to solve a specific subject matter into an automated system. 3) it developed a user friendly interfaces which consist of four functional modules by considering the usability and accessibility of the system user. 4) the developed system was verified by a case study in terms of four kinds of performance indicators.

• Korean Journal of Food Science and Technology
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• v.34 no.5
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• pp.905-910
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• 2002

4-Hydroxyalkenals are cytotoxic aldehydes generated by the oxidation of n-6 and n-3 polyunsaturated fatty acids. To evaluate the potential risk of 4-hydroxyalkenals on Koreans, quantitative data of various oils are necessary. Simultaneous monitoring of 4-hydroxyhexenal and 4-hydroxynoneal in 39 samples including new and used ones through single ion monitoring mode of GC/MS detected both aldehydes in all samples tested, ranging from 0.21 to 26.9 nmol/g for 4-hydroxy-2-hexenal and 0.06 to 56.6 nmol/g for 4-hydroxy-2-nonenal. Frying oils collected from local markets showed 2.28-7.90 and 8.31-30.5 nmol/g of 4-hydroxyhexenal and 4-hydroxynoneal, respectively. National health and nutrition survey data were employed to determine the exposure effect to these 4-hydroxyalkenals from the four most consumed oils in Korea. Daily exposures to hydroxyalkenals excluding possible exposure from fried food were $1.9\;{\mu}g$ from soybean oil, $0.5\;{\mu}g$ from sesame oil, $0.2\;{\mu}g$ from corn oil, and $0.1\;{\mu}g$ from perilla oil. Due to the increasing consumption of polyunsaturated fatty acids in Korea, these data may provide valuable information for evaluating possible physiological effects of 4-hydroxyalkenals from vegetable oils.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.261-266
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• 2007

In this research, we studied an estimating method in client's sight to estimate the total construction cost which is based on the historical cost data at the early stage of the office buildings as a public phase. It is very difficult to analyze the estimation accurately and logically. When a client estimates a project, he/she has to consider there are many issues at the planning step, according as office buildings become gradually diversified as well as their roles continuously extended. Therefore, those are usually make problems for wasting the budget in accordance with the cost estimation errors. Moreover, many kinds of public construction projects, especially such as school, office, sports complex, and the others, have been invested the private finances defined as BTL(Build Transfer Lease) method that are required to manage the detailed process more strictly from initial planning. In order to make an effective planning, the long-term users amount and the building life cycle at the beginning of project should be considered previously and then it may enable to achieve an appropriate project plan. But actually considering overall variables in a building planning is impossible. Accordingly, suggesting a regression model based on the historical cost data from many similar types of office building to support client's role known as estimating the total cost at the early stage. And then performing the test against the proposed model to research the reasonability as using the historical cost data of Japan office buildings.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.597-604
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• 2016

The aim of this study was to prevent the decrease in crop output by disease and insect pests and excessive spraying of agricultural pesticides by application uniformity. A 3m height and 15km/h speed is difficult to maintain with an unmanned helicopter for aerial application, which has been affected by the controlling habits and methods or environmental factors, such as changes in the wind. Therefore, in this study, an aerial application system was design to be attached to an unmanned helicopter, which can allow a controlled application width and spray rate automatically and verified experimentally using Rmax of MS-AVIATION. The size of agricultural land was 50 m2 and nine water sensitive cards were arranged at 1.25m intervals in 5 rows with each row having a 10m interval from the position of 5m. The unmanned helicopter was flying at speeds ranging from 7.2km/h to 17.6km/h and heights ranging from 2.32m to 3.47m. The proposed aerial application system allowed application uniformity by making a valid spraying area of 7.5 m2 with 46423 particles distributed on average.