• Progress in Medical Physics
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• v.24 no.4
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• pp.278-283
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• 2013

Breast cancer is the leading cause of cancer death in women worldwide and the number of women breast cancer patient was increased continuously. Most of breast cancer patient has suffered from unnecessary radiation exposure to heart, lung. Low radiation dose to the heart could lead to the worsening of preexisting cardiovascular lesions caused by radiation induced pneumonitis. Also, several statistical reports demonstrated that left-sided breast cancer patient showed higher mortality than right-sided breast cancer patient because of heart disease. In radiation therapy, Deep Inspiration Breath Hold (DIBH) technique which the patient takes a deep inspiration and holds during treatment and could move the heart away from the chest wall and lung, has showed to lead to reduction in cardiac volume and to minimize the unnecessary radiation exposure to heart during treatment. In this study, we investigated the displacement of heart using DIBH CT data compared to free-breathing (FB) CT data and radiation exposure to heart. Treatment planning was performed on the computed tomography (CT) datasets of 10 patients who had received lumpectomy treatments. Heart, lung and both breasts were outlined. The prescribed dose was 50 Gy divided into 28 fractions. The dose distributions in all the plans were required to fulfill the International Commission on Radiation Units and Measurement specifications that include 100% coverage of the CTV with ${\geq}95%$ of the prescribed dose and that the volume inside the CTV receiving >107% of the prescribed dose should be minimized. Scar boost irradiation was not performed in this study. Displacement of heart was measured by calculating the distance between center of heart and left breast. For the evaluation of radiation dose to heart, minimum, maximum and mean dose to heart were calculated. The present study demonstrates that cardiac dose during left-sided breast radiotherapy can be reduced by applying DIBH breathing control technique.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.5
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• pp.293-299
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• 2007

Intelligent pipeline inspection gauges (PIGs) are inspection vehicles that move along within a (gas or oil) pipeline and acquire signals (also called sensor data) from their surrounding rings of sensors. By analyzing the signals captured in intelligent PIGs, we can detect pipeline defects, such as holes and curvatures and other potential causes of gas explosions. There are two major data access patterns apparent when an analyzer accesses the pipeline signal data. The first is a sequential pattern where an analyst reads the sensor data one time only in a sequential fashion. The second is the repetitive pattern where an analyzer repeatedly reads the signal data within a fixed range; this is the dominant pattern in analyzing the signal data. The existing PIG software reads signal data directly from the server at every user#s request, requiring network transfer and disk access cost. It works well only for the sequential pattern, but not for the more dominant repetitive pattern. This problem becomes very serious in a client/server environment where several analysts analyze the signal data concurrently. To tackle this problem, we devise a fast in-memory cache manager, called T-Cache, by considering pipeline sensor data as multiple time-series data and by efficiently caching the time-series data at T-Cache. To the best of the authors# knowledge, this is the first research on caching pipeline signals on the client-side. We propose a new concept of the signal cache line as a caching unit, which is a set of time-series signal data for a fixed distance. We also provide the various data structures including smart cursors and algorithms used in T-Cache. Experimental results show that T-Cache performs much better for the repetitive pattern in terms of disk I/Os and the elapsed time. Even with the sequential pattern, T-Cache shows almost the same performance as a system that does not use any caching, indicating the caching overhead in T-Cache is negligible.

• Cross-Cultural Studies
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• v.40
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• pp.111-131
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• 2015

An unusual success engendering loyalty among cult fans in the United States, Mamoru Oshii's 1995 cyberpunk anime, Ghost in the Shell (GITS) revolves around a female cyborg assassin named Motoko Kusanagi, a.k.a. "the Major." When the news came out last year that Scarlett Johansson was offered 10 million dollars for the role of the Major in the live action remake of GITS, the frustrated fans accused DreamWorks of "whitewashing" the classic Japanimation and turning it into a PG-13 film. While it would be premature to judge a film yet to be released, it appears timely to revisit the core achievement of Oshii's film untranslatable into the Hollywood formula. That is, unlike ultimately heteronormative and humanist sci-fi films produced in Hollywood, such as the Matrix trilogy or Cloud Atlas, GITS defies a Hollywoodization by evoking much bafflement in relation to its queer, posthuman characters and settings. This essay homes in on Major Kusanagi's body in order to update prior criticism from the perspectives of posthumanism and queer theory. If the Major's voluptuous cyborg body has been read as a liberating or as a commodified feminine body, latest critical work of posthumanism and queer theory causes us to move beyond the moralistic binaries of human/non-human and male/female. This deconstruction of binaries leads to a radical rethinking of "reality" and "identity" in an image-saturated, hypermediated age. Viewed from this perspective, Major Kusanagi's body can be better understood less as a reflection of "real" women than as an embodiment of our anxieties on the loss of self and interiority in the SNS-dominated society. As is warned by many posthumanist and queer critics, queer and posthuman components are too often used to reinforce the human. I argue that the Major's hybrid body is neither a mere amalgam of human and machine nor a superficial postmodern blurring of boundaries. Rather, the compelling combination of individuality, animality, and technology embodied in the Major redefines the human as always, already posthuman. This ethical act of revision-its shifting focus from oppressive humanism to a queer coexistence-evinces the lasting power of GITS.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.11 no.5
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• pp.29-43
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• 2016

The Lean Startup, a methodology for minimizing failure rate of startups, has been receiving attention since its publication in 2011. Although it has been receiving enormous attention as an effective methodology of startups' growth and the emergence of unicorn companies, it is undeniable that the theoretical research and cases on this topic have not been fully accumulated in Korea. Progress of management theory has been made when combining the theory and case studies. In this paper, we thus excavated the 'Cardoc' case, which has applied the lean startup concept to the entire process of service and customer development from the inception of its product design. The following are the findings of the case. First, for the successful application of lean startup, it is essential that all team members to understand the lean startup concept and are willing to apply it thoroughly to the business management. Second, the prompt launching of MVP(Minimum Viable Product) is more important than table discussion. Third, it is crucial to select the appropriate key metrics and analytic tools for effective learning. Fourth, startup must scale up promptly as soon as it verifies the product-market fit through the BML(Build-Measure-Learn) iteration cycle. Fifth, all new business expansion should be lean. Cardoc is currently testing new MVPs in order to move onto the next scale-up process with huge investments in newly added segments. This study is meaningful in that it elaborates the representative case of a Korean startup that has applied the lean startup strategy under the circumstance of insufficient discussion of Korean startup cases in comparison with growing attention both in concept development and case accumulation abroad. We hope that this paper can be a stepping stone for future relevant research on the implementation of lean startup methodology in Korea.

• The Journal of Small Business Innovation
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• v.19 no.2
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• pp.53-68
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• 2016

Motivation and activities for technological learning, entrepreneurship, innovation, and creativity are driving forces of economic development in Asian countries. In the early stages of technological development, technological learning and entrepreneurship are efficient ways in which to catch up with advanced countries because firms can accumulate skills and knowledge quickly at relatively low risk. In the later stages of technological development, however, innovation and creativity become more important. This study aims to identify a) the factors (learning capabilities) that influence technological learning performance and b) barriers to enhancing innovation capabilities for the creative economy and organizations. The major part of this study is related to learning capabilities in the post-catch-up era. Based on a literature review and observations from Korean experiences, this study proposes a technological learning model composed of various influencing factors on technological learning. Three hypotheses are derived, and data are collected from Korean machine tool manufacturers. Intense interviews with CEOs and R&D directors are conducted using structured questionnaires. Statistical analysis, such as correlation and ANOVA are then carried out. Furthermore, this study addresses how to enhance innovation capabilities to move forward. Innovation enablers and barriers are identified by case studies and policy analysis. The results of the empirical study identify several levels of firms' learning capabilities and activities such as a) stock of technology, b) potential of technical labor, c) explicit technological efforts, d) readiness to learn, e) top management support, f) a formal technological learning system, g) high learning motivation, h) appropriate technology choice, and i) specific goal setting. These learning capabilities determine firms' learning performance, especially in the early stages of development. Furthermore, it is found that the critical factors for successful technological learning vary along the stages of technology development. Throughout the statistical and policy analyses, this study confirms that technological learning can be understood as an intrinsic principle of the technology development process. Firms perform proactive and creative learning in the late stages, while reactive and imitative learning prevails in the early stages. In addition, this study identifies the driving forces or facilitating factors enhancing innovation performance in the post catch-up era. The results of the preliminary case studies and policy analysis show some facilitating factors such as a) the strategic intent of the CEO and corporate culture, b) leadership and change agents, c) design principles and routines, d) ecosystem and collaboration with partners, and e) intensive R&D investment.

• Journal of KIISE:Information Networking
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• v.35 no.2
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• pp.99-111
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• 2008

In recent years, the needs for WLANs(Wireless Local Area Networks) technology which can access to Internet anywhere have been dramatically increased particularly in SOHO(Small Office Home Office) and Hot Spot. However, unlike wired networks, there are some unique characteristics of wireless networks. These characteristics include the burst packet losses due to unreliable wireless channel. Note that burst packet losses, which occur when the distance between the wireless station and the AP(Access Point) increase or when obstacles move temporarily between the station and AP, are very frequent in 802.11 networks. Conversely, due to burst packet losses, the performance of 802.11 networks are not always as sufficient as the current application require, particularly when they use TCP at the transport layer. The high packet loss rate over wireless links can trigger unnecessary execution of TCP congestion control algorithm, resulting in performance degradation. In order to overcome the limitations of WLANs environment, MAC-layer LDA(Loss Differentiation Algorithm)has been proposed. MAC-layer LDA prevents TCP's timeout by increasing CRD(Consecutive Retry Duration) higher than burst packet loss duration. However, in the wireless channel with high packet loss rate, MAC-layer LDA does not work well because of two reason: (a) If the CRD is lower than burst packet loss duration due to the limited increase of retry limit, end-to-end performance is degraded. (b) energy of mobile device and bandwidth utilization in the wireless link are wasted unnecessarily by Reducing the drainage speed of the network buffer due to the increase of CRD. In this paper, we propose a new retransmission module based on Cross-layer approach, called BLD(Burst Loss Detection) module, to solve the limitation of previous link layer retransmission schemes. BLD module's algorithm is retransmission mechanism at IEEE 802.11 networks and performs retransmission based on the interaction between retransmission mechanisms of the MAC layer and TCP. From the simulation by using ns-2(Network Simulator), we could see more improved TCP throughput and energy efficiency with the proposed scheme than previous mechanisms.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.2
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• pp.161-174
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• 1997

A study on the distribution of the major domiant species of macrobenthos was carried out in Chinhae Bay from lune 1987 to May 1990. The 13 dominant species, based on the number of individuals and frequency, occupied more than $70\%$ of the total individuals. Of these species, 11 species represented polychaetes $(85\%)$ and 2 species molluscs $(15\%)$. The dominant species included Lumbrineris longifolia, Paraprionospio pinnata and Theora fragilis, with a density of $173.3({\pm}55.4),\;169.3({\pm}257.8)\;and\;81.8({\pm}93.3)\;ind./m^2$, respectively. In terms of biomass these dominant species occupied move than $75\%$ of the total biomass of the macrobenthos. These were composed of 6 species of polychaetes, 7 of molluscs and one echinoderm. The biomass of Macoma tokyoensis, Periglypta cf. puerpera and Paraprionospio pinnata were predominant (more than $45\%$ of the total biomass), and their biomass were $14.69({\pm}30.17),\;8.71({\pm}29.40),\;4.17({\pm}11.93)g/m^2$, respectively. In terms of density, distribution patterns of Lumbrineris iongifolia, Paraprionospio pinnata, Aricidea jeffreysii, Magelona japonica, Sigambra tentaculata, Raetellops pulchella, Glycinde gurjanovae were discussed. In the inner area of the bay with high organic content, Lumbrineris longifolia, Paraprionospio pinnata, Aricides jeffreysii, Sigambra tentaculata, Raetellops pulchella were pvedominant, whereas in the mouth of the bay with low organic content, Magelona japonica, Glycinde gurjanovae, Sternaspis scutata, Theora fragilis were dominant. Lumbrineris longifolia was widly distributed throughout the bay. However, Paraprionospio pinnata, Aricidea jeffreysii and Sigambra tentaculata had high density particularly in the central pan of the bay where there was high organic content in surface sediment, and these species possibly can be used as the potential pollution indicating species.

• Economic and Environmental Geology
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• v.51 no.4
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• pp.381-392
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• 2018

This study examines strategies and implementation plans for commercializing $CO_2$ capture and storage, which is an effective method to achieve the national goal of reducing greenhouse gas. In order to secure cost-efficient business model of $CO_2$ capture and storage, we propose four key strategies, including 1) urgent need to select a large-scale storage site and to estimate realistic storage capacity, 2) minimization of source-to-sink distance, 3) cost-effectiveness through technology innovation, and 4) policy implementation to secure public interest and to encourage private sector participation. Based on these strategies, the implementation plans must be designed for enabling $CO_2$ capture and storage to be commercialized until 2030. It is desirable to make those plans in which large-scale demonstration and subsequent commercial projects share a single storage site. In addition, the plans must be able to deliver step-wised targets and assessment processes to decide if the project will move to the next stage or not. The main target of stage 1 (2019 ~ 2021) is that the large-scale storage site will be selected and post-combustion capture technology will be upgraded and commercialized. The site selection, which is prerequisite to forward to the next stage, will be made through exploratory drilling and investigation for candidate sites. The commercial-scale applicability of the capture technology must be ensured at this stage. Stage 2 (2022 ~ 2025) aims design and construction of facility and infrastructure for successful large-scale demonstration (million tons of $CO_2$ per year), i.e., large-scale $CO_2$ capture, transportation, and storage. Based on the achievement of the demonstration project and the maturity of carbon market at the end of stage 2, it is necessary to decide whether to enter commercialization of $CO_2$ capture and storage. If the commercialization project is decided, it will be possible to capture and storage 4 million tons of $CO_2$ per year by the private sector in stage 3 (2026 ~ 2030). The existing facility, infrastructure, and capture plant will be upgraded and supplemented, which allows the commercialization project to be cost-effective.

• Journal of the Korean Society of Radiology
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• v.13 no.4
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• pp.503-508
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• 2019

In short a binary value according to a change in the tube voltage by using one of VOLUME AXIAL MODE of scanning techniques of chest CT image quality evaluation in order to obtain high image and to present the appropriate tube voltage. CT instruments were GE Revolution (GE Healthcare, Wisconsin USA) model and Phantom used Pediatric Whole Body Phantom PBU-70. The test method was examined in Volume Axial mode using the pediatric protocol used in the Y university hospital of mass-produced material. The tube voltage was set to 70kvp, 80kvp, 100kvp, and mAs was set to smart mA-ODM. The mean SNR difference of the heart was $-4.53{\pm}0.26$ at 70 kvp, $-3.34{\pm}0.18$ at 80 kvp, $-1.87{\pm}0.15$ at 100 kvp, and SNR at 70 kvp was about -2.66 higher than 100 kvp and statistically significant (p<0.05) In the Lung SNR mean difference analysis, $-78.20{\pm}4.16$ at 70 kvp, $-79.10{\pm}4.39$ at 80 kvp, $-77.43{\pm}4.72$ at 100 kvp, and SNR at 70 kvp at about -0.77 higher than 100 kvp were statistically significant. (p<0.05). Lung CNR mean difference was $73.67{\pm}3.95$ at 70 kvp, $75.76{\pm}4.25$ at 80 kvp, $75.57{\pm}4.62$ at 100 kvp and 20.9 CNR at 80 kvp higher than 70 kvp and statistically significant (p<0.05) At 100 kvp of tube voltage, the SNR was close to 1 while maintaining the quality of the heart image when 70 kvp and 80 kvp were compared. However, there is no difference in SNR between 70 kvp and 80 kvp, and 70 kvp can be used to reduce the radiation dose. On the other and, CNR showed an approximate value of 1 at 70 kvp. There is no difference between 80 kvp and 100 kvp. Therefore, 80 kvp can reduce the radiation dose by pediatric chest CT. In addition, it is possible to perform a scan with a short scan time of 0.3 seconds in the volume axial mode test, which is useful for pediatric patients who need to move or relax.

• Archives of design research
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• v.15 no.4
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• pp.275-284
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• 2002

To improve the social and economic position of the disabled people and secure their human rights, an integrated society should be buill. To build such a society, an adequate access should be provided to the movement or in using buildings or facilities. The inconveniences from social life on the part of the disabled people might not result from their impairment or disability, but from physical and social barriers in the environment surrounding them. Therefore, it is necessary to reconstruct entire systems of the society as a disabled people-friendly structure in order to remove those barriers, make them stand their own feet in our communities and freely participate in the social activities. This will eventually lead to build a society in which all people including the disabled people can use those facilities in a more convenient way. It is almost impossible for the disabled people to safely and conveniently access to and use facilities and equipments and freely move to their desired places, without any help from others in Korea. Even though, there are currently many disabled people-related convenience facilities, they have been independently built without a connection with other facilities and buildings, thus not greatly useful. Even when convenience facilities have been built, mostly they are superficially set up; therefore, in many cases, the disabled peOple cannot use those facilities. In this. research, I tried a new concept of mobile wheelchair lift design, which the disabled people can operate without restrictions, when using the public facilities. The key to this research was to develop the existing import-oriented simple functional products to a new system with functional safety and high quality orientation. Also, this research aimed at bringing an. import substitution effect, as well as preempting the mobile wheelchair lift market by advancing into overseas markets through application of new image designs in the field of disabled people aid equipments.