• Journal of Intelligence and Information Systems
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• v.29 no.3
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• pp.249-265
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• 2023

Recently, the satellite industry has been paying attention to the private-led 'New Space' paradigm, which is a departure from the traditional government-led industry. The space industry, which is considered to be the next food industry, is still receiving relatively little attention in Korea compared to the global market. Therefore, the purpose of this study is to explore future signals that can help determine the market entry strategies of private companies in the domestic satellite industry. To this end, this study utilizes the theoretical background of future signal theory and the Keyword Portfolio Map method to analyze keyword potential in patent document data based on keyword growth rate and keyword occurrence frequency. In addition, news data was collected to categorize future signals into first symptom and early information, respectively. This is utilized as an interpretive indicator of how the keywords reveal their actual potential outside of patent documents. This study describes the process of data collection and analysis to explore future signals and traces the evolution of each keyword in the collected documents from a weak signal to a strong signal by specifically visualizing how it can be used through the visualization of keyword maps. The process of this research can contribute to the methodological contribution and expansion of the scope of existing research on future signals, and the results can contribute to the establishment of new industry planning and research directions in the satellite industry.

• The Journal of the Korea Contents Association
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• v.10 no.9
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• pp.68-78
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• 2010

As the IP multicast function is very slowly deployed in Internet due to its scalability problem and inter-domain interoperability problem, interest in the P2P(Peer-to-Peer) streaming technologies for the realtime multimedia multicast applications such as IPTV is highly growing. This paper proposes a P2P streaming method for the QoS-sensitive multimedia multicast applications such as highly-interactive personal IPTV and video conferences. The proposed P2P streaming method allows an application to construct a reliable streaming tree in which a proper number of backup peers are placed according to its reliability requirement. The reliable streaming tree reduces the reconnection delay, occurred in the case of a normal and/or abnormal peer leave, so as to minimize the loss of streaming data. In the proposed P2P streaming method, the join delay of a peer called startup delay is also substantially reduced because the bandwidth and end-to-end delay information of every peer kept in a distributed way allows the target peer for a joining peer to be able to be quickly determined. Moreover, the proposed method's peer admission control mechanism based on the bandwidth and end-to-end delay enables the delay-bounded streaming services to be provided for its corresponding applications.

• Journal of Broadcast Engineering
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• v.19 no.6
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• pp.767-788
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• 2014

The worldwide transition from analog to digital broadcasting has now been completed and the need to study next generation standards for Ultra High Definition TV (UHDTV) broadcasting, and broadcasting & communication convergence systems is rapidly growing. In particular, high resolution mobile broadcasting services are needed to satisfy recent consumers. Therefore, the development of highly efficient convergence broadcasting systems that provide fixed/mobile broadcasting through a single channel is needed. In this paper, a service scenario and requirements for providing 4K UHD & HD convergence broadcasting services through a terrestrial single channel are analyzed by employing the latest transmission and A/V codec technologies. Optimized transmission parameters for 6 MHz & 8 MHz terrestrial bandwidths are drawn, and receiving performances are measured under Additive White Gaussian Noise (AWGN) and time-varying multipath channels. From the results, in a 6 MHz bandwidth, the reliable receiving of HD layer data can be achieved when the receiver velocity is maximum 140 Km/h and is not achieved when the velocity is over 140 Km/h due to the limit of bandwidth. When the bandwidth is extended to 8 MHz, the reliable receiving of both 4K UHD and HD layer data is achieved under a very fast fading multipath channel.

• The KIPS Transactions:PartC
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• v.13C no.3 s.106
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• pp.339-344
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• 2006

Secure delivery of multicast data can be achieved with the use of a group key for data encryption in mobile ad hoc network (MANET) applications based on the group communication. However, for the support of dynamic group membership, the group key has to be updated for each member joining/leaving and, consequently, a mechanism distributing an updated group key to members is required. The two major categories of the group key distribution mechanisms proposed for wired networks are the naive and the tree-based approaches. The naive approach is based on unicast, so it is not appropriate for large group communication environment. On the other hand, the tree-based approach is scalable in terms of the group size, but requires the reliable multicast mechanism for the group key distribution. In the sense that the reliable multicast mechanism requires a large amount of computing resources from mobile nodes, the tree-based approach is not desirable for the small-sized MANET environment. Therefore, in this paper, we propose a new key distribution protocol, called the proxy-based key management protocol (PROMPT), which is based on the naive approach in the small-sized MANET environment. PROMPT reduces the message overhead of the naive through the first-hop grouping from a source node and the last-hop grouping from proxy nodes using the characteristics of a wireless channel.

• Journal of KIISE:Databases
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• v.28 no.3
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• pp.512-527
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• 2001

In a client-server spatial database, it is desirable to maintain the cached data in a client side to minimize the communication overhead across a network. This paper deals with the issues of concurrency and consistency of map updates in this environment. A client transaction to update map data is an interactive work and takes a long time to complete it. The map update in a client site may affect the other sites'updates because of dependencies between spatial data stored at different sites. The concurrent updates should be propagated to the other clients as well as the server to keep the consistency of map replicated in a client cache, and also the communication overhead of the update propagation should be minimized not to lose the benefit of caching. The newly proposed cache region locking with CR lock and CX lock controls the update dependency due to spatial relationships. CS lock and COD lock are suggested to use optimistic detection-based approaches for guaranteeing the consistency of cached client data. The cooperative update protocol uses these extended locking primitives and Spatial Relationship-based 2PC (SR-based 2PC). This paper argues that the concurrent updates of cached client spatial data can be achieved by deciding on collaborative updates or independent updates based on spatial relationships.

• The Journal of Society for e-Business Studies
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• v.27 no.2
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• pp.37-64
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• 2022

As the social acceptance of artificial intelligence increases, the number of cases of applying machine learning methods to companies is also increasing. Technical factors such as accuracy and interpretability have been the main criteria for selecting machine learning methods. However, the success of implementing machine learning also affects management factors such as IT departments, operation departments, leadership, and organizational culture. Unfortunately, there are few integrated studies that understand the success factors of machine learning selection in which technical and management factors are considered together. Therefore, the purpose of this paper is to propose and empirically analyze a technology-management integrated model that combines task-tech fit, IS Success Model theory, and John Rice's algorithm selection process model to understand machine learning selection within the company. As a result of a survey of 240 companies that implemented machine learning, it was found that the higher the algorithm quality and data quality, the higher the algorithm-problem fit was perceived. It was also verified that algorithm-problem fit had a significant impact on the organization's innovation and productivity. In addition, it was confirmed that outsourcing and management support had a positive impact on the quality of the machine learning system and organizational cultural factors such as data-driven management and motivation. Data-driven management and motivation were highly perceived in companies' performance.

• Information Systems Review
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• v.22 no.4
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• pp.75-92
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• 2020

As population and generation structures change, more and more customers tend to avoid facing relation due to the development of information technology and spread of smart phones. This phenomenon consists with efficiency and immediacy, which are the consumption patterns of modern customers who are used to information technology, so offline network-oriented distribution companies actively try to switch their sales and services to untact patterns. Recently, untact services are boosted in various fields, but beauty products are not easy to be recommended through untact services due to many options depending on skin types and conditions. There have been many studies on recommendations and development of recommendation systems in the online beauty field, but most of them are the ones that develop recommendation algorithm using survey or social data. In other words, there were not enough studies that classify segments based on user information such as skin types and product preference. Therefore, this study classifies customer segments using machine learning technique K-prototypesalgorithm based on customer information and search log data of mobile application, which is one of untact services in the beauty field, based on which, untact marketing strategy is suggested. This study expands the scope of the previous literature by classifying customer segments using the machine learning technique. This study is practically meaningful in that it classifies customer segments by reflecting new consumption trend of untact service, and based on this, it suggests a specific plan that can be used in untact services of the beauty field.

• Radiation Oncology Journal
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• v.27 no.1
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• pp.35-41
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• 2009

Purpose: This study was designed to determine the optimum radiotherapy technique for internal mammary node (IMN) irradiation after breast-conserving surgery. Materials and Methods: We selected ten cases of early stage partial mastectomy for plan comparison. Five of the patients were treated to the right-side breast and the rest of the patients were treated to the left-side breast. For each case, four different treatment plans were made to irradiate the entire breast, IMNs and supraclavicular lymph nodes (SCLs). The four planning techniques include a standard tangential field (STF), wide tangential field (WTF), partially wide tangential field (PWT) and a photon-electron mixed field (PEM). We prescribed a dose of 50.4 Gy to the SCL field at a 3 cm depth and isocenter of the breast field. Results: The dose distribution showed clear characteristics depending on the technique used. All of the techniques covered the breast tissue well. IMN coverage was also good, except for the STF, which was not intended to cover IMNs. For the cases of the left-side breasts, the volume of the heart that received more than 30 Gy was larger (in order) for the WTF, PWT, PEM and STF. For radiation pneumonitis normal tissue complication probability (NTCP), the PWT showed the best results followed by the STF. Conclusion: Despite the variety of patient body shapes, the PWT technique showed the best results for coverage of IMNs and for reducing the lung and heart dose.

• Journal of Conservation Science
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• v.36 no.6
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• pp.578-590
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• 2020

During the 1960-1970s, a group of ceramic conservation scientists and ceramic historians in South Korea came together and established their own disciplines. While the two disciplines share the same ceramics as the subjects of their research, there has been little interaction between the two as their research outputs are articulated in remarkably different languages. This paper aims to address the following questions by using a case study that focuses on the research on white porcelains centered on the project of Gyeonggi Museum and a series of studies conducted by one of the museum's project research teams. First, what are the characteristics of and differences between the explanation styles of the two disciplines that share the same research subjects of ceramics? Second, why has the communication between the two disciplines become difficult? Third, if there can be a trading zone wherein the two disciplines would be able to communicate again, what would be its epistemic conditions? The focus of this paper is the relationship between scientific data and ordinary language, which the two disciplines have shared from their inception. By analyzing the relationship, I first argue that, as the analytical techniques of conservation science have become more developed, conservation science's data have gradually lost its relevance in ceramic history, in spite of a shared common language between them; Second, I argue that by recovering the import of shared language again, the scientific data can be placed in a different practical context, providing novel interpretations that are relevant and often consequential to ceramic history.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.5
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• pp.486-492
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• 2004

In this paper, we newly propose the binary CA-CDMA(constant amplitude CDMA) system using pre-coding method to solve the high PAPR problem caused by multi-user signal transmission in the CDMA system. 4-user CA-CDMA, the basis of proposed binary CA-CDMA system, makes binary output signal for 4 input users. It produces the output of binary(${\pm}$2) amplitude by using a parity signal resulting from the XOR operation of 4 users data. Another sub-channel or more bandwidth is not necessary because it is transmitted together with user data and can be easily recovered in the receiver. The extension of the number of users can be possible by the simple repetition of the basic binary 4-user CA-CDMA. For example, binary 16-user CA-CDMA is made easily by allocating the four 4-user CA-CDMA systems in parallel and leading the four outputs to the fifth 4-user CA-CDMA system as input, because the output signal of each 4-user CA-CDMA is also binary. By the same extension procedure, binary 64 and 256-user CA-CDMA systems can be made with the constant amplitude. As a result, the code rate of this proposed CA-CDMA system is just 1 and binary CA-CDMA does not change the transmission rate with the constant output signal(PAPR = 0 ㏈). Therefore, the power efficiency of the HPA can be maximized without the nonlinear distortion. From the simulation results, it is verified that the conventional CDMA system has multi-level output signal, but the proposed binary CA-CDMA system always produces binary output. And it is also found that the BER of conventional CDMA system is increased by nonlinear HPA, but the BER of proposed binary CA-CDMA system is not changed.