• 한국멀티미디어학회논문지
• /
• 제10권2호
• /
• pp.260-268
• /
• 2007

현재의 컴퓨터 및 모바일 분야의 게임 개발은 C/C++ 언어와 DirectX를 사용한 게임 개발을 주로 하고 있다. 하지만 이러한 제한된 개발 언어의 사용은 여러 유형의 게임 엔진 제작에 있어 게임 엔진의 다양화를 억제하는 요소가 된다. 본 논문은 제한된 게임 개발 언어의 사용을 다양화 시키는 목적으로 자바를 이용하여 게임을 개발하고자 하였다. 특히 자바의 특징 중 코드의 재사용성을 이용하여 게임 엔진에서의 코드 재사용과 확장성을 고려한 게임으로 비행기 전투 게임인 메타버스 게임 엔진을 설계하고 개발하였다.

• 통합자연과학논문집
• /
• 제11권4호
• /
• pp.197-203
• /
• 2018

Long Term Evolution-Advanced (LTE-A) is the next drive in the broadband mobile communication, which allows operators to improve networks performance and service capabilities. LTE-A targets the peak data rates of 1Gbps in the downlink and 500Mbps in the uplink. This requirement is only fulfilled by a transmission bandwidth of up to 100MHz. However the accessibility of such large part of the contiguous spectrum is uncommon in practice. Therefore LTE-A uses some new features on top of the existing LTE standards to provide very high data rate transmission. Some of the most significant features introduced in LTE-A are carrier aggregation, heterogeneous network enhancement, coordinated multipoint transmission and reception, enhanced multiple input and multiple output, and development relay nodes with universal frequency reuse. This review paper presents an overview of the above mentioned LTE-A key features and functionalities. Based on this review, in the conclusion we discuss the current technical challenges for future broadband mobile communication systems.

• 신재생에너지
• /
• 제17권2호
• /
• pp.24-31
• /
• 2021

Renewable energy has become more popular with the increase in the use of solar power. Consequently, the disposal of defective and old solar panels is gradually increasing giving rise to a new problem. Furthermore, the efficiency and power output decreases with aging. Researchers worldwide are engaged in solving this problem by developing eco-module technologies that restore and reuse the solar panels according to the defect types rather than simple disposal. The eco-module technology not only solves the environmental problem, but also has economic advantages, such as extending the module life. Replacement of encapsulants contributes to a major portion of the module maintenance plan, as the degradation of encapsulants accounts for 60% of the problems found in modules over the past years. However, the current International Electrotechnical Commission (IEC) standard testing was designed for the commercialization of solar modules. As the problem caused by long-term use is not considered, this method is not suitable for the quality assurance evaluation of the eco-module. Therefore, to design a new accelerated test, this paper provides an overview of EVA degradation and comparison with the IEC and accelerated tests.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제16권8호
• /
• pp.2648-2665
• /
• 2022

Device-to-device (D2D) multicast has become a promising technology to provide specific services within a small geographical region with a high data rate, low delay and low energy consumption. However, D2D multicast communications are allowed to reuse the same channels with cellular uplinks and result in mutual interference in a cell. In this paper, an intelligent channel assignment algorithm is designed in D2D underlaid cellular networks with the target of maximizing network throughput. We first model the channel assignment problem to be a throughput maximizing problem which is NP-hard. To solve the problem in a feasible way, a novel channel assignment algorithm is proposed. The key idea is to find the appropriate cellular communications and D2D multicast groups to share a channel without causing critical interference, i.e., finding a channel for a D2D multicast group which generates the least interference to network based on current channel assignment status. In order to show the efficacy and effectiveness of our proposed algorithm, a novel search algorithm is proposed to find the near-optimal solution as the baseline for comparisons. Simulation results show that the proposed algorithm improves the network throughput.

• 국제학술발표논문집
• /
• The 7th International Conference on Construction Engineering and Project Management Summit Forum on Sustainable Construction and Management
• /
• pp.52-61
• /
• 2017

Considering its significant impact on the cost and schedule of construction projects, formwork as one part of temporary facility categories in construction should be arranged precisely. Current practice in the formwork planning is often conducted manually and repetitively, causing low efficiency and time waste. This study proposes an automated framework to generate more accurate and detailed formwork plans by utilizing information from building information modeling (BIM) considering the adequate geometric and semantic information provided by the BIM model. The dimensions and quantities information of elements in a building can be extracted automatically. Then, a rule is prepared for calculating the required forms erected around elements based on the contact areas. Finally, an algorithm of integrating first fit decreasing (FFD) with coordinated bottom left (CBL) is applied to automatically generate the formwork plan. The BIM-based automated planning framework is demonstrated by an illustrative example. The results show that the proposed framework can generate the formwork plan accurately and automatically, and significantly improve the efficiency in the formwork plan and reuse.

• 국제학술발표논문집
• /
• The 8th International Conference on Construction Engineering and Project Management
• /
• pp.387-396
• /
• 2020

Wearable biosensors have the potential to non-invasively and continuously monitor seniors' stress in their daily interaction with the urban environment, thereby enabling to address the stress and ultimately advance their outdoor mobility. However, current wearable biosensor-based stress detection methods have several drawbacks in field application due to their dependence on batch-learning algorithms. First, these methods train a single classifier, which might not account for multiple subjects' different physiological reactivity to stress. Second, they require a great deal of computational power to store and reuse all previous data for updating the signle classifier. To address this issue, we tested the feasibility of online multi-task learning (OMTL) algorithms to identify multiple seniors' stress from electrodermal activity (EDA) collected by a wristband-type biosensor in a daily trip setting. As a result, OMTL algorithms showed the higher test accuracy (75.7%, 76.2%, and 71.2%) than a batch-learning algorithm (64.8%). This finding demonstrates that the OMTL algorithms can strengthen the field applicability of the wearable biosensor-based stress detection, thereby contributing to better understanding the seniors' stress in the urban environment and ultimately advancing their mobility.

• 한국표면공학회지
• /
• 제57권2호
• /
• pp.92-97
• /
• 2024

The LiBr aqueous solution, which is the absorption liquid of absorption refrigerator, must be replaced periodically because the concentration of impurities such as Cu²⁺, Fe²⁺, Ca²⁺, etc., increases due to corrosion of the tubes as the period of use increases, and the refrigeration efficiency decreases significantly. In order to reuse the waste absorption liquid, flocculation-precipitation method is mainly applied to precipitate the impurities, which requires hundreds of times the concentration of impurities and generates additional waste. In this study, a process for removing Cu ion impurities from cyclone electrolyzer by electrolytic reduction is presented in a small-scale facility without additional waste. It was confirmed that Cu ion impurities can be removed down to 1 ppm by electrolytic reduction process, and to further improve the removal rate, the mass transfer rate was increased by using a cyclone electrolyzer. The removal rate of Cu ions increased with the increase of flow rate and current density, and it was confirmed that Cu was removed at a rate of 1.48 ppm/h under the condition of 330 mL/sec and 2.5 mA/cm².

• Clinical Endoscopy
• /
• 제56권3호
• /
• pp.263-267
• /
• 2023

Climate change is a global emergency. Consequently, current global targets to combat the climate crisis include reaching net-zero carbon emissions by 2050 and keeping global temperature increases below 1.5 ℃. In 2014, the healthcare carbon footprint was 5.5% of the total national footprint. Gastrointestinal endoscopy (GIE) has a large carbon footprint compared to other procedures performed in healthcare facilities. GIE was identified as the third largest generator of medical waste in healthcare facilities for the following reasons: (1) GIE is associated with high case volumes, (2) GIE patients and relatives travel frequently, (3) GIE involves the use of many nonrenewable wastes, (4) single-use devices are used during GIE, and (5) GIE is frequently reprocessed. Immediate actions to reduce the environmental impact of GIE include: (1) adhering to guidelines, (2) implementing audit strategies to determine the appropriateness of GIE, (3) avoiding unnecessary procedures, (4) using medication rationally, (4) digitalization, (5) telemedicine, (6) critical pathways, (7) outpatient procedures, (8) adequate waste management, and (9) minimizing single-use devices. In addition, sustainable infrastructure for endoscopy units, using renewable energy, and 3R (reduce, reuse, and recycle) programs are necessary to reduce the impact of GIE on the climate crisis. Consequently, healthcare providers need to work together to achieve a more sustainable future. Therefore, strategies must be implemented to achieve net-zero carbon emissions in the healthcare field, especially from GIE, by 2050.

• 한국환경보건학회지
• /
• 제42권3호
• /
• pp.160-168
• /
• 2016

Objectives: Materials coming into contact with food may result in the migration of chemical substances into the food. To protect consumers from exposure, Regulation (EU) No. 10/2011 specifies the use of standard migration tests. Polyethylene terephthalate (PET), widely used for food packaging materials, has drawn the attention of researchers because unwanted migration of PET into food might occur when consumers reuse packaging material. The aim of this study was to predict and develop a migration model for two components, acetaldehyde and butyraldehyde in PET, into food simulants under conditions of changing pH and solvents, such as those observed in fermented foods like kimchi or sauerkraut. Methods: Using a migration model based on Fick's second law of diffusion in one dimension, the migration of acetaldehyde and butyraldehyde from PET into a simulant of fermented food at $20^{\circ}C$ over 10 days was evaluated. The simulant for fermented food was modelled as 10% ethanol for three days, followed by 3% acetic acid for seven days. Results: The migration of acetaldehyde into the 10% ethanol was 0.36 times that of a simulated fermented food system, while that of butyraldehyde was 1.34 times greater. These results may have been influenced by the chemical interactions among the migrants, polymers and simulants, as well as by the solubilities of the migrants in polymers and simulants. Conclusion: Because food simulants have a limited capacity to mimic real food systems under the current migration model, an appropriate simulant and migration test should be considered in the case of increasing acidity. Furthermore, since the accuracy of the worst-case estimation of migration predicted by the current model is severely limited under changing food conditions, food simulants and their interactions should be further investigated with respect to conservative migration modelling.

• 한국산학기술학회논문지
• /
• 제13권5호
• /
• pp.2305-2312
• /
• 2012

시대의 변화에 따른 IT 기술의 급속한 발전은 전반적인 산업영역에서 예전보다 쉽게 정보를 취득하고 가공할 수 있는 여건을 형성하고 있다. 최근 각광 받고 있는 SNS의 변화를 살펴보면 스마트폰 이용이 대중화되면서 마케팅 툴로서의 가치가 더욱 급부상하고 있다. 본 연구는 패션 마케팅 분야에서 새로운 시장으로 떠오르고 있는 Facebook 활용 사례를 연구하였다. 패션업체 10곳을 선정하여 활동지표의 기준이 되는 '게시글', 'like this', 'people talking about this' '이벤트'를 중심으로 페이스북 페이지를 연구하였고 spearman 순위 상관계수를 이용하여 위 지표들 간의 상관분석을 실시하였다. 연구 결과 '게시글'과 'like this'의 관계는 높은 상관관계를 보여 주었고 다른 요인들 사이에서는 상관관계를 확인할 수 없었다. 페이스북 페이지를 이용한 마케팅은 소비자와 업체와의 소통이 기존 매체에 비해 원활하였는데 이는 SNS의 마케팅의 이용이 기존의 마케팅의 한계였던 소통의 벽을 넘을 수 있음을 보여주는 결과였다.