• 제목/요약/키워드: history of science and technology

검색결과 921건 처리시간 0.261초

70점 체육교사의 삶과 고백: 교사로서 회의감의 근원에 대한 생애사 연구 (C Grade Physical Education Teacher's Life and Confession : A Life History Research on root of Skepticism as a Physical Education Teacher)

  • 장승현;임새미
    • 한국응용과학기술학회지
    • /
    • 제38권4호
    • /
    • pp.1195-1208
    • /
    • 2021
  • 본 연구는 체육교사로서 회의감의 근원적 문제를 찾는데 목적이 있다. 이를 위해 이준호 체육교사를 연구 참여자로 선정하고 생애사 연구방법을 활용하였다. 그 결과, 1) '스테레오타입과 문화', 2) '훈육의 변화', 3) '혼란과 자책', 4) '참교사가 아닌 보통교사'의 내용이 도출되었다. 그 결과, 이준호 교사를 괴롭혀온 회의감은 '변화의 아이러니'로 설명될 수 있었으며, 그것은 '비동시성의 동시성'이라는 근원적 배경에서 비롯된 것임을 확인시켜주었다. 결국, 학교 내 존재하는 '비동시성의 동시성'의 모순으로 인해 이준호 교사의 감정적 소진은 필연적 귀결이었으며 그것은 한편으로 그가 이 시대의 평범한 체육교사임을 보여주고 한국사회 평범한 체육교사들의 삶과 고민을 이해하는데 도움을 주었다고 판단된다.

운전자의 위험운전 행동 분석을 통한 시내버스 안전운전 지원 서비스 기회 도출 (Identifying Service Opportunities for Enhancing Driving Safety of Intra-City Buses Based on Driving Behavior Analysis)

  • 김민준;임치현;이창호;김광재;전진우;박용성
    • 대한산업공학회지
    • /
    • 제41권5호
    • /
    • pp.499-510
    • /
    • 2015
  • The purpose of this research is to identify new service opportunities for enhancing driving safety of intra-city buses based on driving behavior analysis. Service opportunity identification involves finding target customers of service (to whom), motivations for service (why), service contents (what), and service delivery process (when, where). This paper presents an analysis of driving behaviors using the operational data of intra-city buses in conjunction with traffic accident data and drivers' driving history data. This paper also presents four identified service opportunities based on the data analysis results. This research would contribute to enhancing driving safety of intra-city buses in Korea and serve as a basis for developing new services for driving safety enhancement.

Mode Coupling within Inner Cladding Fibers

  • Lee, Byeong-Ha;Eom, Tae-Jung;Kim, Myoung-Jin;Paek, Un-Chul;Park, Tae-Sang
    • Journal of the Optical Society of Korea
    • /
    • 제7권2호
    • /
    • pp.53-58
    • /
    • 2003
  • We report the formation of inner cladding modes in the optical fiber having an inner cladding structure. The inner cladding layer located between the core- and the cladding- layers of a conventional fiber might have, so called, inner cladding mode(s). The brief history of the inner cladding fiber and the spectral properties of the inner cladding mode are presented. By utilizing fiber gratings, the spectral properties of the inner cladding mode formed in Dispersion Compensating Fiber (DCF) are discussed. It was observed that one resonant peak of a long-period fiber grating was not sensitive to the variation on the cladding surface. With a fiber Bragg grating, a small group of unusual resonant Peaks was observed between the main Bragg Peak and the series of usual Peaks resulted from the mode coupling to counter-propagating cladding modes. Within the DCF by using fiber gratings, it is noted, at least one mode can be coupled to the inner cladding mode and a few outer cladding modes are severely affected by the inner cladding of the fiber.

Secure Authentication Approach Based New Mobility Management Schemes for Mobile Communication

  • Abdelkader, Ghazli;Naima, Hadj Said;Adda, Ali Pacha
    • Journal of Information Processing Systems
    • /
    • 제13권1호
    • /
    • pp.152-173
    • /
    • 2017
  • Mobile phones are the most common communication devices in history. For this reason, the number of mobile subscribers will increase dramatically in the future. Therefore, the determining the location of a mobile station will become more and more difficult. The mobile station must be authenticated to inform the network of its current location even when the user switches it on or when its location is changed. The most basic weakness in the GSM authentication protocol is the unilateral authentication process where the customer is verified by the system, yet the system is not confirmed by the customer. This creates numerous security issues, including powerlessness against man-in-the-middle attacks, vast bandwidth consumption between VLR and HLR, storage space overhead in VLR, and computation costs in VLR and HLR. In this paper, we propose a secure authentication mechanism based new mobility management method to improve the location management in the GSM network, which suffers from a lot off drawbacks, such as transmission cost and database overload. Numerical analysis is done for both conventional and modified versions and compared together. The numerical results show that our protocol scheme is more secure and that it reduces mobility management costs the most in the GSM network.

PCRM: Increasing POI Recommendation Accuracy in Location-Based Social Networks

  • Liu, Lianggui;Li, Wei;Wang, Lingmin;Jia, Huiling
    • KSII Transactions on Internet and Information Systems (TIIS)
    • /
    • 제12권11호
    • /
    • pp.5344-5356
    • /
    • 2018
  • Nowadays with the help of Location-Based Social Networks (LBSNs), users of Point-of-Interest (POI) recommendation service in LBSNs are able to publish their geo-tagged information and physical locations in the form of sign-ups and share their experiences with friends on POI, which can help users to explore new areas and discover new points-of-interest, and promote advertisers to push mobile ads to target users. POI recommendation service in LBSNs is attracting more and more attention from all over the world. Due to the sparsity of users' activity history data set and the aggregation characteristics of sign-in area, conventional recommendation algorithms usually suffer from low accuracy. To address this problem, this paper proposes a new recommendation algorithm based on a novel Preference-Content-Region Model (PCRM). In this new algorithm, three kinds of information, that is, user's preferences, content of the Point-of-Interest and region of the user's activity are considered, helping users obtain ideal recommendation service everywhere. We demonstrate that our algorithm is more effective than existing algorithms through extensive experiments based on an open Eventbrite data set.

Evaluation of the inhibitory effect of Gynostemma pentaphyllum extracts on CYP450 enzyme activities using LC-MS/MS

  • Jun Sang Yu;Young Seok Ji;So Young Jo;Xiang-Lan Piao;Hye Hyun Yoo
    • Mass Spectrometry Letters
    • /
    • 제14권3호
    • /
    • pp.116-119
    • /
    • 2023
  • Gynostemma pentaphyllum (Thunb.) Makino extract, a natural product with a history of traditional use, has gained attention for its potential health benefits. This study aimed to investigate its effects on key cytochrome P450 (CYP) enzymes using LC-MS/MS. Human liver microsomes and cDNA-expressed CYP2C8, CYP2C9, CYP2C19, and CYP3A4 supersomes were employed. Enzyme activity was assessed based on the formation of CYP-specific marker metabolites. The resulting data showed that the extract exhibited inhibitory effects on CYP2C8, CYP2C9, CYP2C19, and CYP3A4. Thus, G. pentaphyllum extract may influence the pharmacokinetics of drugs metabolized by CYP2C8, CYP2C9, CYP2C19, and CYP3A4. These findings emphasize the importance of considering potential herb-drug interactions when incorporating this extract into therapeutic regimens or dietary supplements.

The Complete Mitochondrial Genome of the Fourhorn Sculpin Triglopsis quadricornis (Perciformes, Cottidae) from Sirius Passet, North Greenland

  • Kim, Bo-Mi;Kihm, Ji-Hoon;Park, Tae-Yoon S.
    • Ocean and Polar Research
    • /
    • 제43권4호
    • /
    • pp.371-374
    • /
    • 2021
  • Triglopsis quadricornis Linnaeus, 1758 (Cottidae) is distributed in the Atlantic and Arctic and has four unique bony protuberances on its head. Here, we report the complete, circular, and annotated mitochondrial genome of T. quadricornis. The complete T. quadricornis mitochondrion was sequenced by high-throughput Illumina HiSeq platform. The sequences are 16,736 bp in size and contains 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, a control region, and large and small ribosomal subunits. The overall genomic structure of T. quadricornis mitochondrion was conserved with the gene arrangement of Megalocottus and Myoxocephalus species, and phylogenetic analysis supports their sister relationships. Most PCGs consist of TAA or TAG as a termination codon, whereas COII, ND4, and CYTB have T-- as a stop codon. This complete mitochondrial DNA information of T. quadricornis will provide an essential genomic resource to elucidate the phylogenetic relationship and evolutionary history of the family Cottidae.

Two New Marine Sponges of the Genus Halichondria (Halichondrida: Halichondriidae) from Uljin, Korea

  • Kang, Dong-Won;Sim, Chung-Ja
    • Animal Systematics, Evolution and Diversity
    • /
    • 제27권1호
    • /
    • pp.19-23
    • /
    • 2011
  • Two new marine sponges, Halichondria jangseungenesis n. sp. and H. nagokenesis n. sp., of the family Halichondriidae, were collected from Uljin-gun, Gyeongsangbuk-do, Korea by SCUBA diving during the period from Apr 2007 to Aug 2007. Based on their spicule composition and skeletal structure, H. jangseungenesis n. sp. appears to have a close similarity with H. panicea (Pallas, 1766); however, they differ in length of spicule. The spicule length of oxea of H. jangseungenesis n. sp. is shorter than that of H. panicea. Based on their spicule composition and growth form, H. nagokenesis n. sp. is quite similar to H. cylindrata Tanita and Hoshino, 1989; however, but they differ in length of spicule. The spicule length of oxea of H. nagokenesis n. sp. is longer than that of H. cylindrata.

Optimization of modal load pattern for pushover analysis of building structures

  • Shayanfar, Mohsen Ali;Ashoory, Mansoor;Bakhshpoori, Taha;Farhadi, Basir
    • Structural Engineering and Mechanics
    • /
    • 제47권1호
    • /
    • pp.119-129
    • /
    • 2013
  • Nonlinear Static Procedures (NSPs) have been developed as a practical tool to estimate the seismic demand of structures. Several researches have accomplished to minimize errors of NSPs, namely pushover procedures, in the Nonlinear Time History Analysis (NTHA), as the most exact method. The most important issue in a typical pushover procedure is the pattern and technique of loading which are extracted based on structural dynamic fundamentals. In this paper, the coefficients of modal force combination is focused involving a meta-heuristic optimization algorithm to find the optimum load pattern which results in a response with minimum amount of errors in comparison to the NTHA counterpart. Other parameters of the problem are based on the FEMA recommendations for pushover analysis of building structures. The proposed approach is implemented on a high-rise 20 storey concrete moment resisting frame under three earthquake records. In order to demonstrate the effectiveness and robustness of the studied procedure the results are presented beside other well-known pushover methods such as MPA and the FEMA procedures, and the results show the efficiency of the proposed load patterns.

수중 운동체의 거동 및 표면 압력하중 예측에 관한 수치적 연구 (A Computational Study About Behavior of an Underwater Projectile and Prediction of Surficial Pressure Loading)

  • 조성민;권오준
    • 한국군사과학기술학회지
    • /
    • 제20권3호
    • /
    • pp.405-412
    • /
    • 2017
  • In the present study, two phase flows around a projectile vertically launched from an underwater platform have been numerically investigated by using a three dimensional multi-phase RANS flow solver based on pseudo-compressibility and a homogeneous mixture model on unstructured meshes. The relative motion between the platform and projectile was described by six degrees of freedom(6DOF) equations of motion with Euler angles and a chimera technique. The propulsive power of the projectile was modeled as the fluid force acting on the lower surface of the body by the compressed air emitted from the platform. Qualitative analysis was conducted for the time history of vapor volume fraction distributions. Uncorking pressure around the projectile and platform was analyzed to predict impact force acting on the surfaces. The results of 6DOF analysis presented similar tendency with the surficial pressure distributions.