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Performance Evaluation of End-to-End Security Protocols in WiBro using NS-2 (NS-2를 이용한 WiBro상에서의 종단 간 보안 프로토콜의 성능평가 및 분석)

  • Kim, Jung-Yoon;Song, Se-Hwa;Kim, In-Hwan;Hwang, In-Yong;Kim, Seok-Joong;Choi, Hyoung-Kee
    • Journal of KIISE:Information Networking
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    • v.36 no.3
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    • pp.184-190
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    • 2009
  • WiBro has advantages when both WLAN and 3G UMTS are adopted. Much research is being carried out in this area. However, the WiBro specification does not consider end-to-end security. Hence, another security protocol has to be adopted to support secure communication. Most previous research only focused on WiBro MAC performance improvement or security. In this paper, we adopt a security protocol such as IPsec, TLS, and DTLS, well known end-to-end security protocols, to make full use of WiBro in the IP network. Using NS-2 we simulated the adoption of end-to-end security protocol and evaluated performance and usability. Simulation shows DTLS had some performance advantages. All the protocols, TLS and IPsec are also suitable for use in WiBro.

A Simulation for the Characteristics of the Sound-Pipe of King Song-Dok Bell (시뮬레이션에 의한 성덕대왕 신종 음관의 특성)

  • Choi Myung-Jin;Park Hong-Eul
    • Journal of the Korea Society for Simulation
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    • v.14 no.4
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    • pp.69-76
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    • 2005
  • To investigate the characteristics of the sound-pipe on the top of King Song-Dok bell, using computer simulation, the throat impedance was evaluated for the straight pipe and conical pipes with varying taper angles. When sound propagates in a rigid walled, unflanged circular pipe with wavelength larger than radius, the acoustic motion is planar, much as in a bar. The incident sound waves are reflected at the end of pipe and some of them are transmitted. The reflection coefficient and radiation impedance of the sound-pipe of King Song-Dok bell were calculated, and the results demonstrated that the high frequency sound is radiated through the sound-pipe. It behaves like a frequency filter.

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Preliminary Load Tests for the Design of Large Diameter Drilled Shaft by Bi-directional Loading Method at Toe (대구경 현장타설말뚝의 설계를 위한 선단재하방법에 의한 시험말뚝 재하시험)

  • Song, Myung-Jun;Park, Yung-Ho;Kim, Dong-Jun
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.89-98
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    • 2005
  • Preliminary pile load tests for the design of large diameter drilled shaft were performed on two of reduced scale(D=1370mm) test piles. The maximum loads of 2350 tonf in each direction were applied using bi-directional hydraulic jacks(Osterberg Cell) at toe. Neither of the test piles yielded in terms of skin friction and end bearing. Comparisons of the test results with several methods that estimate pile capacity show that the method of Horvath and Kenney(1979) for skin friction and Zhang and Einstein(1998) for end bearing were most appropriate for the site. The test results were directly applied to pile design in case RQD of skin and toe was larger than that of the test pile. It is desirable, therefore, to consider not only unconfined compression strength but also rock mass properties(i.e. TCR, RQD) for skin friction and end bearing evaluation in the future.

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A Performance Analysis of Multi-GNSS Receiver with Various Intermediate Frequency Plans Using Single RF Front-end

  • Park, Kwi Woo;Chae, Jeong Geun;Song, Se Phil;Son, Seok Bo;Choi, Seungho;Park, Chansik
    • Journal of Positioning, Navigation, and Timing
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    • v.6 no.1
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    • pp.1-8
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    • 2017
  • In this study, to design a multi-GNSS receiver using single RF front-end, the receiving performances for various frequency plans were evaluated. For the fair evaluation and comparison of different frequency plans, the same signal needs to be received at the same time. For this purpose, two synchronized RF front-ends were configured using USRP X310, and PC-based software was implemented so that the quality of the digital IF signal received at each front-end could be evaluated. The software consisted of USRP control, signal reception, signal acquisition, signal tracking, and C/N0 estimation function. Using the implemented software and USRP-based hardware, the signal receiving performances for various frequency plans, such as the signal attenuation status, overlapping of different systems, and the use of imaginary or real signal, were evaluated based on the C/N0 value. The results of the receiving performance measurement for the various frequency plans suggested in this study would be useful reference data for the design of a multi-GNSS receiver in the future.

End of life Nursing Care Through a Visiting Nurse in Long-Term Care Insurance: A Case Report using the OMAHA System (방문간호사의 생애말기 환자 간호사례: 오마하시스템을 활용하여)

  • Song, Yeon Yi;Park, Eun Jin
    • Journal of Korean Academy of Rural Health Nursing
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    • v.16 no.2
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    • pp.60-68
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    • 2021
  • Purpose: This case report was attempted to present the process of the end of life nursing care provided by the visiting nurse. Methods: The subject was a person who was decided the long-term care Grade 1 and received a visiting nursing service, and the service was terminated on the death, and then was selected as a case with the consent of his family. The data were collected through long-term care benefit provision records and interviews with the visiting nurse. The nursing process was presented by applying the Omaha System. Results: The subject had digestion-hydration problems and respiration problems in the physiological domain, and the problems of role change, caretaking/parenting, spirituality, and grief in the psychosocial domain were identified. Depending on the problem, the end of life nursing care was provided to the subject and family members through activities on physical symptoms/signs, dietary management, end-life care, and coping skills. Conclusion: We expect that if the visiting nurse provides anticipatory guidance on the death process, the subject will be able to prepare for death comfortably with the family at home instead of vague fear of death.

Transcatheter closure of small ductus arteriosus with amplatzer vascular plug

  • Cho, Eun Hyun;Song, Jinyoung;Kang, I-Seok;Huh, June;Lee, Sang Yoon;Choi, Eun Young;Kim, Soo Jin
    • Clinical and Experimental Pediatrics
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    • v.56 no.9
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    • pp.396-400
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    • 2013
  • Purpose: The purpose of this study was to share our experience of transcatheter closure of small patent ductus arteriosus (PDA) by using an Amplatzer vascular plug (AVP). Methods: We reviewed the medical records of 20 patients who underwent transcatheter closure at Samsung Medical Center and Sejong General Hospital from January 2008 to August 2012. The size and shape of the PDAs were evaluated by performing angiograms, and the PDA size and the AVP devices size were compared. Results: The mean age of the patients was $54.9{\pm}45.7$ months old. The PDAs were of type C (n=5), type D (n=12), and type E (n=3). The mean pulmonary end diameter of the PDA was $1.7{\pm}0.6$ mm, and the aortic end diameter was $3.6{\pm}1.4$ mm. The mean length was $7.3{\pm}1.8$ mm. We used 3 types of AVP devices: AVP I (n=5), AVP II (n=7), and AVP IV (n=8). The ratio of AVP size to the pulmonary end diameter was $3.37{\pm}1.64$, and AVP size/aortic end ratio was $1.72{\pm}0.97$. The aortic end diameter was significantly larger in those cases repaired with AVP II than in the others (P=0.002). The AVP size did not significantly correlate with the PDA size, but did correlate with smaller ratio of AVP size to aortic end diameter ($1.10{\pm}0.31$, P=0.032). Conclusion: Transcatheter closure of small PDA with AVP devices yielded satisfactory outcome. AVP II was equally effective with smaller size of device, compared to others.

The Shear and Friction Characteristics Analysis of Inconel 718 during End-milling process using Equivalent Oblique Cutting System I -Up Endmilling- (등가경사절삭 시스템에 의한 Inconel 718 엔드밀링 공정의 전단 및 마찰특성 해석 I -상향 엔드밀링-)

  • Lee, Young-Moon;Yang, Seung-Han;Choi, Won-Sik;Song, Tae-Seong;Gwon, O-Jin;Choe, Yong-Hwan
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.2
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    • pp.79-86
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    • 2002
  • In end milling process the undeformed chip thickness and the cutting force components vary periodically with phase change of the tool. In this study, up end milling process is transformed to the equivalent oblique cutting. The varying undeformed chip thickness and the cutting force components in end milling process are replaced with the equivalent average ones. Then it can be possible to analyze the chip-tool friction and shear process in the shear plane of the end milling process by the equivalent oblique cutting system. According to this analysis, when cutting Inconel 718, 61, 64 and 55% of the total energy is consumed in the shear process with the helix angle 30$^{\circ}$, 40$^{\circ}$ and 50$^{\circ}$ respectively, and the balance is consumed in the friction process. With the helix angle of 40$^{\circ}$ the specific cutting energy consumed is smaller than with the helix angle 30$^{\circ}$ and 50$^{\circ}$.