• Journal of the Semiconductor & Display Technology
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• v.22 no.4
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• pp.124-130
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• 2023

Recently, fan out wafer level packaging, which enables high integration, miniaturization, and low cost, is being rapidly applied in the semiconductor industry. In particular, FOWLP is attracting attention in the mobile and Internet of Things fields, and is recognized as a core technology that will lead to technological advancements such as 5G, self-driving cars, and artificial intelligence in the future. However, as chip density and package size within the package increase, FOWLP warpage is emerging as a major problem. These problems have a direct impact on the reliability and electrical performance of semiconductor products, and in particular, cause defects such as vacuum leakage in the manufacturing process or lack of focus in the photolithography process, so technical demands for solving them are increasing. In this paper, warpage simulation according to the thickness of FOWLP material was performed using finite element analysis. The thickness range was based on the history of similar packages, and as a factor causing warpage, the curing temperature of the materials undergoing the curing process was applied and the difference in deformation due to the difference in thermal expansion coefficient between materials was used. At this time, the stacking order was reflected to reproduce warpage behavior similar to reality. After performing finite element analysis, the influence of each variable on causing warpage was defined, and based on this, it was confirmed that warpage was controlled as intended through design modifications.

• Journal of KIISE:Information Networking
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• v.35 no.6
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• pp.521-528
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• 2008

Such conventional maritime communication technologies as radio have short some comings in their transmission quality. It can be overcome by wireless channels provided by satellites such as INMARSAT, which nevertheless suffer from the high costs. In this paper, we propose a novel technology resolving the above problems, featuring in the establishment of maritime communication networks with multi-hop structures. The inter vessel and ship-to- shore networks previously modeled after MANET are remodeled by SANET (Ship Ad Hoc Networks) in the present work. Fan-shaped Search Zone Routing (FSR) protocol also is presented, which utilizes not only static geographical information including the locations of ports and the navigations of courses but also the unique characteristics of ships in terms of mobile nodes. The FSR finds the fan-shaped search zone on which the shortest path is located. The performance of LAR protocol is compared with that of FSR in several ways. First, FSR does not make use of a type of control packets as beaconing data, resulting in a full utilization of the bandwidth of the wireless channels. Second, the delivery rate by the FSR is 100% for the fan-shaped search zone includes at least one route between source and destination nodes on its border line, where as that of LAR has been turned out to be 64%. Third, the optimality of routes searched by the FSR is on a 97% level. Of all, the FSR shows a better performance than LAR by about 50%.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.425-428
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• 2002

To understand and forecast the wireless internet market in Korea, we will analyse the network externalities in wireless internet market into communication network externalities and hardware/software network externalities. The wireless market has two competing streams, one is mobile internet and the other is wireless fan internet. Both are characterized by strong network externalities which lead to increasing return to stale. Mobile internet is supposed more suitable for communication and WLAN for data. However these two system will compete in some area, and the critical factor to deride the winner is supposed to be the network externalities as in so many other high-tech industries had showed.

• Journal of Information Processing Systems
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• v.14 no.1
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• pp.56-78
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• 2018

Security issue in mobile ad hoc network (MANET) is a promising research. In 2011, we had accomplished a survey of black hole attacks in MANETs. However network technology is changing with each passing day, a vast number of novel schemes and papers have been proposed and published in recent years. In this paper, we survey the literature on malicious attacks in MANETs published during past 5 years, especially the black hole attack. Black hole attacks are classified into non-cooperative and collaborative black hole attacks. Except black hole attacks, other attacks in MANET are also studied, e.g., wormhole and flooding attacks. In addition, we conceive the open issues and future trends of black hole detection and prevention in MANETs based on the survey results of this paper. We summarize these detection schemes with three systematic comparison tables of non-cooperative black hole, collaborative black hole and other attacks, respectively, for a comprehensive survey of attacks in MANETs.

• Science of Emotion and Sensibility
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• v.20 no.3
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• pp.23-38
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• 2017

In order to identify effective approaches for creating more viral Facebook posts, this research conducted an empirical content analysis of leading Korean brands' Facebook fan-pages (Samsung Mobile, SK Telecom, Kia Motors, and POSCO). Their distinctive visual storytelling and communication patterns were investigated as effective user engagement triggers. Through analysis of the research results, it was statistically proved that the different industrial attributes of the four brands, which are primarily characterized by their product (or service) types, affect their Facebook posting patterns by showing different engaging rates (measured by like, comment, and share metrics). In addition, the user engagement rates of the posts were influenced by their visual storytelling factors (i.e. ad objective, value scale, and visual media types). In line with these statistical findings, the distinctive visual storytelling strategies of the four brands were identified. Moreover, competitive and uncompetitive visual storytelling tactics were suggested according to the ad objectives and visual media types on Facebook.

• Journal of Power System Engineering
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• v.20 no.3
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• pp.64-73
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• 2016

In this research work, an algorithm development on tracking end-point of aerial work platform with jib profile and bend-linked boom was carried out to find the X, Y and Z direction value using coordinate transformation matrix. This matrix consists of device status value(length and angle) based on camera position axis, which are sent from device controller PLUS+1 by CAN protocol. These values are used to measure the distance and angle from the camera to the end-point. Using these distance and angle value, monitoring system controls FAN/TILT/ZOOM status of camera to get an adequate scene of workplace. This program was written in Java, C# and C for mobile device. These results provide the information to the aerial work device for secure operation.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11b
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• pp.1531-1534
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• 2002

주로 음성 트래픽을 처리하는 2G CDMA/PCS 시스템과 달리 CDMA2000 및 IxEV-DO 와 같은 차세대 이동통신시스템은 음성 트래픽뿐 만 아니라 패킷형태의 데이터 트래픽도 처리해야 하므로 차세대 이동통신망의 설계 및 디멘져닝을 위해서는 무엇보다도 데이터 트래픽의 주요 특성인 버스트성(Burstiness)과 자기유사성(Self-similarity)이 반영된 트래픽 모델이 요구된다. 이러한 관점에서 본 논문에서는 데이터 트래픽 특성이 서로 다른 다수의 데이터 트래픽의 통합되어 망에 입력되는 경우의 성능을 시뮬레이션 하였고, 그 결과를 해석적 모델인 Norros의 Effective Bandwidth Formula및 Z. FAN의 Bahadur-Rao Theorem을 적용한 Formula와도 비교하였다.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.2
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• pp.23-34
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• 2013

Over the past several decades in the microelectronics industry, devices have gotten smaller, thinner, and lighter, without any accompanying degradation in quality, performance, and reliability. One permanent and deniable trend in packaging as well as wafer fabrication industry is system integration. The proliferating options for system integration, recently, are driving change across the overall semiconductor industry, requiring more investment in developing, ramping and supporting new die-, wafer- and board-level solution. The trend toward 3D system integration and miniaturization in a small form factor has accelerated even more with the introduction of smartphones and tablets. In this paper, the key issues and state of the art for system integration in the packaging process are introduced, especially, focusing on ease transition to next generation packaging technologies like through silicon via (TSV), 3D wafer-level fan-out (WLFO), and chip-on-chip interconnection. In addition, effective solutions like fine pitch copper pillar and MEMS packaing of both advanced and legacy products are described with several examples.

• Journal of the Korean Society of Safety
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• v.18 no.4
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• pp.71-77
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• 2003

To inject fresh air into a fire room, Positive Pressure Ventilation (PPV) can be used and the blower of PPV increases inside pressure of the room. It makes high flow rate of products of combustion, smoke and heat from the structure, and it is very helpful to fireman on the fire extinguishing work. The flame moves to the direction of airflow and the temperature of flame can be decreased rapidly. In this experiment, a water mist system is applied to PPV to increase the effectiveness, and various effective factors are studied. n-Heptane and pine wood stick were used as fuel. Temperatures at the above and behind the combustion pan were strongly reduced by the water mist system and by the convective cooling with airflow. The smoke density was also decreased by PPV with water mist system and it can be explained by the absorption of smoke particles on the water mist droplet and by the strong exhausting effects of mobile fan.

• International journal of advanced smart convergence
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• v.8 no.1
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• pp.196-203
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• 2019

We have reviewed the potential impact of blockchain technology on the music industry by analyzing the views of academia and the industry experts. The music industry had rapid changes from the physical market to the digital market in the past decades. The consumers download and stream music online and mobile during the digital dominant market. While streaming music has been recently growing at a fast rate, fair distribution of revenue to the artists continues to be an issue. Some industry experts believe that the issue of fair distribution of revenue to the artist may be resolved using blockchain technology, while some are skeptical about the application or the duration of impact. The blockchain may enhance speedier payment using smart contracts, provide additional revenue and promote the music if excellent fan support is achieved. The positive impact on the music industry may only be possible if there are detailed consideration of the industry and careful understanding of the customers.