• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.311-314
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• 2002

This paper has been studied a Image watermarking using PN coding operation where frequency band. By using wavelet transformation, This gets high frequency place HH2 where image watermark puts. Also this places that PN code and binary image are operated. And then, this paper has designed image watermarking index process and extract process, watermarked image which are to add noise is able to extract watermark.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.27 no.4
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• pp.90-93
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• 2004

This paper is case study for ISO 9001/2000 quality management system certification of social welfare. We constructed quality management system for efficient operation for service quality improvement of welfare hall which is society welfare facilities. This paper evaluated operation actual conditions of "G" welfare hall which introduce and operates quality management system according to index of evaluate for society welfare hall and present improvement plan about effect and problem.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.315-316
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• 2019

This paper proposes the operation scheme and control method for a four-level hybrid half-bridge flying-capacitor inverter (4L-HHBFCI). With in-phase disposition level-shifted modulation (IPD), the flying capacitor voltage ripple is less than 1% of the reference value, while the line-to-line voltage total harmonic distortion is 23.27% at unity modulation index. The performance and effectiveness of the proposed inverter operation have been verified by simulation results.

• Journal of Korean Institute of Industrial Engineers
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• v.36 no.1
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• pp.59-68
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• 2010

The medical emergency departments are suffering from the crowdness of patients, hence the quality of medical service the patients are receiving are getting poorer. Overcrowding of medical emergency departments may incur the waiting time for the treatment, and the improper treatment in time. For the operational control of the emergency department, the crowding index is commonly used to identify the crowding intensity, with which the operation process is managed, and future process can be expected. In this study the composite crowding index is suggested, in which the trend of inpatients rate, the age and acuity of patients, and resource of ED are considered. The validity of the suggested crowding index is discussed by the regression analysis for the index and the actual number of inpatients, and by the simulation study using the process model and the real data.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.8
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• pp.1500-1506
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• 2015

In this paper, en efficient broadcast scheme with acknowledged mode is proposed. Specifically, based on stochastic pattern of ACK/NACK across all users and index coding, adaptive coding scheme with XOR operation is used at the transmitter. At each receiver, packets are decoded using layered decoding method with already successfully decoded packets. From numerical results, proposed index coded broadcast scheme is shown to be more efficient than naive broadcast scheme in the sense of average total number of transmitted packets.

• Journal of Positioning, Navigation, and Timing
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• v.6 no.3
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• pp.117-123
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• 2017

In this paper, we propose a performance index that can compare the position estimation performance according to the time slot allocation order, which is superior in the position estimation performance in the operation of the Link-16 based relative navigation system. In order to verify the validity of the performance index, a software-based Link-16 relative navigation system performance analysis platform composed of a signal generator, a signal reception and navigation algorithm execution unit, and a performance analysis unit was designed. Using the designed software platform, we analyzed the relationship between proposed performance index and position estimation performance according to time slot allocation order in the same position reference (PR) arrangement. The performance index of the proposed time slot allocation is expected to be utilized not only for the Link-16 system, but also for the Time Division Multiple Access (TDMA)-based navigation system.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.3
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• pp.325-334
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• 2011

Market Environment around water work industry is rapidly changing. ISO, International Organization for Standardization, announced the international water work service standard for comparison and evaluation between nations and businesses. And developed countries in water work are introducing market principle for growth of nation's water industry and reinforcement of its competitiveness. Also, some local governments entrusted their water utilities for improvement of competitiveness of water work. However, as some failure cases from overseas came out with emphasis, there are many refuting perspective about entrusted operation achievements of domestic water market. Hence, this paper evaluated competitiveness of domestic local water utilities from the perspective of productivity. After evaluating productivity using Malmquist productivity index, the authors compared and analyzed whether there is a difference of productivity between two different operating types by using Mann-Whitney test. As a result of analysis, it has shown that local water utilities achieved higher productivity at entrusted operation type rather than direct operation type. The local water utilities which chose entrusted operation had increased the productivity 13.9% on total factor productivity(TFP) during experimenting period, while the local water utilities which chose direct operation had increased 0.2%. The background of achieving this high productivity in entrusted operation was analyzed as a result of the higher technological effectiveness of a special water company. The result of this study can be referred when local government needs to decide on what operating types they will use.

• Journal of the Korean association of regional geographers
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• v.3 no.2
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• pp.105-120
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• 1997

One of the most important issues of object-oriented geographical database system is to develop an indexing technique which enables more efficient I/O processing within aggregation hierarchy or inheritance hierarchy. Up to present, several indexing schemes have been developed for this purpose. However, they have separately focused on aggregation hierarchy or inheritance hierarchy of object-oriented data model. A recent research is proposing a nested-inherited index which combines these two hierarchies simultaneously. However, this new index has some weak points. It has high storage costs related to its use of auxiliary index. Also, it cannot clearly represent the inheritance relationship among classes within its index structure. To solve these problems, this thesis proposes a pointer-chain index. Using pointer chain directory, this index composes a hierarchy-typed chain to show the hierarchical relationship among classes within inheritance hierarchy. By doing these, it could fetch the OID list of objects to be retrieved more easily than before. In addition, the pointer chain directory structure could accurately recognize target cases and subclasses and deal with "select-all" typed query without collection of schema semantic information. Also, it could avoid the redundant data storing, which usually happens in the process of using auxiliary index. This study evaluates the performance of pointer chain indexing technique by way of simulation method to compare nested-inherited index. According to this simulation, the pointer chain index is proved to be more efficient with regard to storage cost than nested-inherited index. Especially in terms of retrieval operation, it shows efficient performance to that of nested-inherited index.

• Journal of the Society of Disaster Information
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• v.11 no.2
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• pp.203-209
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• 2015

The heat detector detects heat in the fire and is an important core element of the automatic fire alarm system used generally for every fire prevention objects. The heat detector is distinguished in spot type and spread type and in spot type, there are differential and thermistor types. These heat detectors give a great influence on the loss of people and property according to the sensitivity of response such as operation time and operation temperature in actual fire and in overseas people apply it for the development of products that can be operated in the early stage of fire including certification, quality management, and comparison standard by introducing response time index through the theory of heat balance that considers the heat loss and ventilation tests. In Korea, the response time index is introduced and used in the head of sprinkler products, but it is not applied to the heat detector at present. It is necessary to introduce the response time index that shows the sensitivity of response of the heat detector the installation standard for the heat detector that the response time index is applied should be different according to the fire weight, danger degree of fire, and shape of buildings. Through this study, it tries to help reduce lives and property of people through the swift warning by installing detectors suitable for the building structure.

• Journal of Korean Society of Forest Science
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• v.112 no.3
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• pp.303-321
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• 2023

To develop the Forest Work Load Index (FWLI) for estimating the work intensity of forest workers, a study focused on forest tending was conducted. To estimate the FWLI, we used the Ovako Working Posture Analysis System (OWAS) and the Work Load Index (WLI). The OWAS is a prominent method used for analyzing musculoskeletal load in work tasks, and WLI is a prominent method used for analyzing the work intensity of workers. The PRI values analyzed for each forest tending project were 185.3 (Thinning), 150.6 (Pruning), 181.1 (Thinning for Forest Fire Prevention), and 197.0 (Thinning for Young Trees). The WLI values, calculated on the basis of the measured heart rates, were 59.5% (Thinning), 53.5% (Pruning), 56.2% (Thinning for Forest Fire Prevention), and 62.3% (Thinning for Young Trees). The FWLI was calculated using the analyzed PRI and WLI values. The FWLI values for the forest tending project were 110.2 (Thinning), 80.7 (Pruning), 102.1 (Thinning for Forest Fire Prevention), and 123.0 (Thinning for Young Trees). The FWLI developed in this study can be used to quantitatively compare the workloads of forest workers. In the future, the analyzed FWLI can be used as a basis for improving forest workers' postures and comparing workloads across different forest projects.