• 한국정보통신설비학회:학술대회논문집
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• 2005.08a
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• pp.120-123
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• 2005

본 논문에서는 무선 홈 네트워크에 사용될 홈 내 무선 LAN(Local Area Network)용 안테나에 대해 연구하였다. 홈 내의 천장 부근에 안테나를 설치할 경우, 전파의 외부 노출을 피하고 최소한의 전력이 각 홈 별로 공급되어야하며, 각 홈 내에서의 전파를 홈 내 위치마다 균등하게 분배되어야 한다. 이를 위하여 모노폴 안테나와 다이폴 안테나 및 마이크로스트립 패치 안테나를 무선랜 주파수 2.4GHz를 중심으로 설계 제작하여 그 특성들을 고찰하였다. 그 결과 브로드사이드 방향으로 최대 또는 null 지점 발생, 좁은 빔폭 등 무선랜용 안테나로 사용하기 적합하지 않았다. 따라서, 구조적 변형 등을 통한 방사 빔의 개선 연구가 필요하다.

• Journal of Chest Surgery
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• v.31 no.4
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• pp.422-426
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• 1998

Progressive dysphagia in a 53 year old man was caused by a giant polypoid tumor in the lower intrathoracic esophagus. Radical transthoracic esophagectomy and esophagogastrostomy were carried out. Microscopic examination of the tumor revealed a true carcinosarcoma, composed of a mixture of basaloid squamous cell carcinoma and chondrosarcoma with multiple cartilagenous productions. Carcinoma metastases were found in the subcarinal and perigastric lymph nodes. Immunohistochemically, squamous area displayed strong positive to cytokeratin, and basaloid area showed positive immunoreaction to high molecular weight cytokeratin (34${\beta}$E12). Spindle cell sarcoma reacted to vimentin and smooth muscle actin. Chondrosarcomatous area reacted to vimentin and S-100 protein. He received postoperative chemotherpy and radiotherapy. He has been free of disease for 11 months.

• The Korean Journal of Urological Oncology
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• 제15권3호
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• pp.103-110
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• 2017

Cancer is the tissue complex consisted with heterogeneous cellular compositions, and microenvironmental cues. During the various stages of cancer initiation, development, and metastasis, cell-cell interactions as well as cell-extracellular matrix play major roles. Conventional cancer models both 2-dimensional and 3-dimensional (3D) present numerous limitations, which restrict their use as biomimetic models for drug screening and fundamental cancer biology studies. Recently, bioprinting biofabrication platform enables the creation of high-resolution 3D structures. Moreover this platform has been extensively used to model multiple organs and diseases, and this versatile technique has further found its creation of accurate models that figure out the complexity of the cancer microenvironment. In this review we will focus on cancer biology and limitations with current cancer models and we discuss vascular structures bioprinting that are critical to the construction of complex 3D cancer organoids. We finally conclude with current literature on bioprinting cancer models and propose future perspectives.

• Journal of Information Technology Services
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• v.18 no.3
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• pp.117-128
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• 2019

The remarkable achievements of the artificial intelligence in recent years are also raising awareness about its potential risks. Several governments and public organizations have been proposing the artificial intelligence ethics for sustainable development of artificial intelligence by minimizing potential risks. However, most existing proposals are focused on the developer-centered ethics, which is not sufficient for the comprehensive ethics required for ongoing intelligent information society. In addition, they have chosen a number of principles as the starting point of artificial intelligence ethics, so it is not easy to derive the guideline flexibly for a specific member reflecting its own situation. In this paper, we classify primitive members who need artificial intelligence ethics in intelligent information society into three : Developer, Supplier and User. We suggest a new artificial intelligence ethics, Seoul PACT, with minimal principles through publicness (P), accountability (A), controllability (C), and transparency (T). In addition, we provide 38 canonical guidelines based on these four principles, which are applicable to each primitive members. It is possible for a specific member to duplicate the roles of primitive members, so that the flexible derivation of the artificial intelligence ethics guidelines can be made according to the characteristics of the member reflecting its own situation. As an application example, in preparation for applying artificial intelligence to e-government service, we derive a full set of artificial intelligence ethics guideline from Seoul PACT, which can be adopted by the special member named Korean Government.

• The Journal of Korean Obstetrics and Gynecology
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• v.28 no.1
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• pp.147-157
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• 2015

Objectives: We report two cases that have an effective result with Korean traditional medical treatment to two patients who have uterine fibroids, using transabdominal ultrasonography for checking the size of uterine fibroids. Methods: A 44-year-old patient and a 43-year-old patient were treated with an herbal medicine, acupuncture and cupping therapy. We followed up the symptoms and the size of uterine fibroids. Results: The 44-year-old patient was asymptomatic, her size of the uterine fibroid was reduced for 6 months. Also, the 43-year-old patient experienced that the symptoms such as urinary frequency, ovulation pain, heavy bleeding were improved and the size of the uterine fibroid was reduced. Conclusions: This results suggest that Korean traditional medical treatment if effective for both asymptomatic and symptomatic uterine fibroids and ultrasonography is useful for checking the effect of Korean traditional medical treatment. Further case series and studies are warranted.

• Journal of Korean Clinical Nursing Research
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• v.24 no.3
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• pp.273-282
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• 2018

Purpose: This descriptive study was conducted to identify the effects of hospital organizational culture and work environment on nurses' intent to stay at work. Methods: Participants of this study were 234 nurses who have worked at a local general hospital in the Chungcheong province for at least 6 months. The data were collected from July 17 to 28, 2017, using self-reported questionnaires and analyzed with multiple regression using SPSS version 22.0. Results: Clinical experience (${\beta}=.38$, p<.001), institutional support (${\beta}=.33$, p<.001), and relation-oriented culture (${\beta}=.24$, p<.001) affected intent to stay at work among nurses. These variables accounted for 34.8% of the variance in intent to stay at work among nurses. Conclusion: This study confirms the effects of the work environment and organizational culture on nurses' intent to stay at work. Efforts for improving the work environment and organizational culture need for retaining nurses in a hospital. We suggest further research to identify the other factors associated with intent to stay at work among nurses.

• Journal of Platform Technology
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• v.10 no.1
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• pp.3-10
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• 2022

In high-risk workplaces where communication is not possible, such as deforestation, it is necessary to use equipment that monitors the worker's situation in real time and obtains information according to the worker's location in case of an emergency. This paper analyzes the development and demonstration experiments of smart hard hats for deforestation workers to maintain a safe working environment. The developed smart helmet identifies the location of the worker based on the UWB signal for location estimation, and it is necessary to keep the distance between the workers not too close. UWB, Gyro, and LoRa are used to communicate even in the communication shadow area. It is used to provide a safe working environment such as improved construction to reduce worker risks and risks in forest working environments.

• The Journal of Korea Robotics Society
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• v.17 no.3
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• pp.339-346
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• 2022

To operate in real environment, humanoid robots should be able to react to unknown disturbances. To deal with disturbances, various robust control algorithms have been developed for decades. But for collaborative works such as teleoperation system, a compliance control can be the better solution for disturbance reactions. In this paper, a center of mass (CoM) compliance control algorithm for humanoid robots is proposed. The proposed algorithm is based on the state observer and positive feedback of disturbance. With the state observer based on humanoid CoM control performance model, disturbance in each direction can be observed. The positive feedback of disturbances to the reference CoM trajectory enables compliant motion. The main contributions of this algorithm are achieving compliance independently in each axis and maintaining balance against external force. Through dynamic simulations, the performance of the proposed method was demonstrated. Under two types of disturbance conditions, humanoid robot DYROS-JET reacted with compliant motion via the proposed algorithm.

• Journal of Platform Technology
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• v.11 no.4
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• pp.80-88
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• 2023

To construct a learning model in the field of artificial intelligence, a dataset should be collected and be delivered to the central server where the learning model is constructed. Federated learning is a machine learning method building a global learning model without transmitting data located in a client side in a collaborative manner. It can be used to protect privacy, and after constructing a local trained model on individual clients, the parameters of the local model are aggregated centrally to update the global model. In this paper, we reuse the existing learning parameter to improve federated learning, describe incremental federated learning. For this work, we do experiments using the federated learning framework named Flower, and evaluate the experiment results with regard to elapsed time and precision when executing optimization algorithms.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.1202-1205
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• 2011

본 논문에서는 스마트폰 소셜 네트워크 서비스(Social Network Service)인 트위터(Twitter)를 이용한 원격 데이터베이스 모니터링 시스템을 제안하였다. 제안한 시스템을 통해 원격 데이터베이스를 모니터링할 경우 기존 상용화된 CS(Client-Server)기반 모니터링 방식에 비해 다음과 같은 장점들이 있다. 첫째, 웹 애플리케이션 기반 사용자 인터페이스를 사용하기 때문에 프로그램 유지보수의 문제가 발생하지 않으며, 웹 브라우저를 통한 인터넷 접속이 가능한 환경이라면 언제 어디서든 시간과 공간의 제약 없이 원격 데이터베이스의 모니터링이 가능하다. 둘째, 제안한 시스템은 원격 데이터베이스 모니터링 시 중앙관리서버에 통합 저장되어 있는 원격 데이터베이스들의 상태정보를 사용하므로 관리자 접속이 증가할 경우 데이터베이스에 대한 연결세션과 질의수행 증가로 인해 데이터베이스 성능에 영향을 미칠 수 있는 CS 기반 모니터링 방식과 달리 데이터베이스 성능에 영향을 미치지 않는다. 셋째, 제안한 시스템은 관리자가 모니터링을 수행하고 있지 않은 상황에서 원격 데이터베이스에 문제가 발생할 경우 이를 트위터를 통해 관리자의 스마트폰으로 즉시 통보하므로 관리자가 해당 문제를 실시간으로 확인할 수 있다.