• 시큐리티연구
• /
• 제59호
• /
• pp.37-69
• /
• 2019

자치경찰제는 연구자의 시각과 이해 관계자의 입장에 따라 다양한 의견 제시가 가능하다. 즉, '권한 분산', '정치적 중립성', '재정 문제', '총체적 치안안전 역량'을 비롯한 여러 가지 기준을 어떻게 조화롭게 담아내느냐에 따라 한국적 자치경찰의 성패가 좌우된다. 자치경찰제의 본격적 도입을 앞둔 상황에서, 제주자치경찰의 그간 운영 경과와 평가는 요긴한 학습 자료가 되리라 본다. 특히, 경찰청에서 지난해부터 '제주자치경찰 사무확대'를 추진 중인데, 이것은 향후 자치경찰 도입을 앞둔 각 지방자치단체의 입장에서는 매우 유익한 참고서가 될 것이다. 제주자치경찰에 대한 이제까지의 평가는 다소 비판적 시각이 우세해보인다. 하지만, 대다수 평가가 인력·장비·법령·조직을 비롯한 하드웨어 측면의 접근이 많았던 반면, 조직문화와 운영시스템, 사무절차를 비롯한 소프트웨어 측면의 접근은 부족했던 점이 아쉬움을 남긴다. 본 연구에서는 제주자치경찰 사무확대 1년을 맞아 각종 문헌과 보고서, 통계자료, 언론 보도 등을 토대로 그간의 성과와 정책적 시사점을 살펴보고자 한다. 연구 결과, 향후 자치 경찰제가 연착륙하기 위해서는 먼저, 지방행정과 치안행정의 연계를 강화해야 하고, 둘째, 국가·지방 양 측이 탄탄한 협업 기반을 구축해야 하며, 셋째, 지방자치에 단체자치를 뛰어 넘어 주민 자치적 요소를 보강해야 하고, 넷째, 국가·지방 전반에 걸쳐 상황대응 역량을 고도화하는 한편, 끝으로 자치경찰제 도입의 워킹그룹으로서 '기관 간 실무협의체'를 활성화해야 한다는 시사점을 이끌어 내었다. 자치경찰제 연구는 현재진행형이다. 후속 연구에서는 더욱 풍성한 자료를 토대로 보다 다양화된 접근 방법을 통해 깊이 있는 연구가 있었으면 한다. 특히, 가외성과 형평성을 비롯한 추가 이념에 대한 고찰이 필요하고, 저출산·노령화와 4차 산업혁명, 통일시대를 비롯한 거시적 트렌드 변화에 맞춰 대한민국 자치경찰의 장기 청사진을 제시하는 연구가 뒤따르기를 열망한다.

• Geomechanics and Engineering
• /
• 제8권3호
• /
• pp.377-390
• /
• 2015

The governing equations of wave propagation in one dimension of elastic continuum materials are investigated by taking the influence of the initial stress into account. After a short review of the theory of elastic wave propagation in a rock mass with an initial stress, results indicate that the initial stress differentially influences P-wave and S-wave propagation. For example, when the initial stress is homogeneous, for the P-wave, the initial stress only affects the magnitude of the elastic coefficients, but for the S-wave, the initial stress not only influences the elastic coefficients but also changes the governing equation of wave propagation. In addition, the P-wave and S-wave velocities were measured for granite samples at a low initial stress state; the results indicate that the seismic velocities increase with the initial stress. The analysis of the previous data of seismic velocities and elastic coefficients in rocks under ultra-high hydrostatic initial stress are also investigated.

• 한국소음진동공학회논문집
• /
• 제16권1호
• /
• pp.57-65
• /
• 2006

In this paper, we present the principle of virtual work, from which the exact non-linear equations of motion of a rotating ring can be derived, by using the theory of finite deformation. For a thin ring of which the effect of variation in curvature across the cross-section is neglected, the radial displacement and the extensional stress are determined from the principle of virtual work at the steady state where the ring is rotating with a constant angular velocity. And also we formulate systematically the governing equations concerned to the in-plane vibrations and the out-of-plane vibrations at the disturbed state by using the principle of virtual work which is expressed with the disturbed displacements about the steady state. The formulated governing equations are classified by four models along the cases of considering or neglecting all or partly the secondary effects of flexural shear, rotary inertia, circumferential extension, and twist inertia. The natural vibrations of thin rings are analyzed, and its results are compared and discussed.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2005년도 추계학술대회논문집
• /
• pp.585-592
• /
• 2005

In this paper, we present the principle of virtual work, from which the exact non-linear equations of motion of a rotating ring can be derived, by using the theory of finite deformation For a thin ring of which the effect of variation in curvature across the cross-section is neglected, the radial displacement and the extensional stress are determined from the principle of virtual work at the steady state where the ring is rotating with a constant angular velocity. And also we formulate systematically the governing equations concerned to the in-plane vibrations and the out-of-plane vibrations at the disturbed state by using the principle of virtual work which is expressed with the disturbed displacements about the steady state. The formulated governing equations are classified by four models along the cases of considering or neglecting all or partly the secondary effects of flexural shear, rotary inertia, circumferential extension, and twist inertia. The natural vibrations of thin rings are analyzed, and its results are compared and discussed.

• Structural Engineering and Mechanics
• /
• 제52권4호
• /
• pp.787-813
• /
• 2014

Starting with Hamilton's variational principle, the governing field equations for the steady state response of thin-walled beams under harmonic forces are derived. The formulation captures shear deformation effects due to bending and warping, translational and rotary inertia effects and as well as torsional flexural coupling effects due to the cross section mono-symmetry. The equations of motion consist of four coupled differential equations in the unknown displacement field variables. A general closed form solution is then developed for the coupled system of equations. The solution is subsequently used to develop a family of shape functions which exactly satisfy the homogeneous form of the governing field equations. A super-convergent finite element is then formulated based on the exact shape functions. Key features of the element developed include its ability to (a) isolate the steady state response component of the response to make the solution amenable to fatigue design, (b) capture coupling effects arising as a result of section mono-symmetry, (c) eliminate spatial discretization arising in commonly used finite elements, (d) avoiding shear locking phenomena, and (e) eliminate the need for time discretization. The results based on the present solution are found to be in excellent agreement with those based on finite element solutions at a small fraction of the computational and modelling cost involved.

• Earthquakes and Structures
• /
• 제24권3호
• /
• pp.217-235
• /
• 2023

Orthogonal pairs of rollers on concave beds (OPRCB) are a low-cost, low-tech rolling-based isolating system, whose high efficiency has been shown in a previous study. However, seismic performance of OPRCB isolators has only been studied in the two-dimensional (2D) state so far. This is while their performance in the three-dimensional (3D) state differs from that of the 2D state, mainly since the vertical accelerations due to rollers' motion in their beds, simultaneously in two orthogonal horizontal directions, are added up and resulting in bigger vertical inertia forces and higher rolling resistance. In this study, first, Lagrange equations were used to derive the governing equations of motion of the OPRCB-isolated buildings in 3D. Then, some regular shear-type OPRCB-isolated buildings were considered subjected to three-component excitations of far- and near-source earthquakes, and their responses were compared to those of their fixed-base counterparts. Finally, the effects of more realistic modeling and analysis were examined by comparing the responses of isolated buildings in 2D and 3D states. Response histories were obtained by the fourth-order Runge-Kutta-Nystrom method, considering the geometrical nonlinearity of isolators. Results reveal that utilizing the OPRCB isolators effectively reduces the acceleration response, however, depending on the system specifications and earthquake characteristics, the maximum responses of isolated buildings in the 3D state can be up to 40% higher than those in the 2D state.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 1996년도 추계학술대회논문집; 한국과학기술회관, 8 Nov. 1996
• /
• pp.255-259
• /
• 1996

This paper presents active vibration control of a rotating cantilevered beam using piezoceramic actuators. A governing equation of motion is obtained by the Hamilton's principle and expressed in the state space representation. Subsequently, an H$_{\infty}$ control which is robust to system uncertainties is synthesized through the loop shaping design procedure. Computer simulations for the steady-state vibration control are undertaken in order to demonstrate the effectiveness and robustness of the proposed control methodology..y.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2001년도 추계학술대회 논문집
• /
• pp.134-138
• /
• 2001

Basic governing equations for the Active Magnetic Bearing system are derived. Characteristic difference between PD and PID controllers are studied. It is shown that I-control action is able to minimize the steady state error and increase the stiffness in low frequency range.

• Ocean and Polar Research
• /
• 제39권2호
• /
• pp.149-158
• /
• 2017

The opsin family of light sensitive proteins family makes up are the universal photoreceptor molecules of all visual systems in the vertebrates including teleosts. They can change their conformation from a resting state to a signaling state upon light absorption, which activates the G-protein coupled receptor, thereby resulting in a signaling cascade that produces physiological responses. However, this species is poorly characterized at molecular level due to little sequence information available in public databases. We have investigated the opsin family of nocturnal cutlass fish using the whole transcriptome sequencing method. The opsin genes were cloned and its expression in the tissues and organs were examined by qPCR. We cloned 6 opsin genes (RRH, Opn4, Rh1, Rh2, VA-opsin, and Opn3) in retina and brain tissue. It contained the seven presumed transmembrane domains that are characteristic of the G-protein-coupled receptor family. However, short wavelength sensitive pigment (SWS) and long wavelength sensitive pigment (LWS) were not detected in this study. The mRNA expression of the 6 photoreceptor genes were detected in retina and peripheral tissue. Our studies will lead to further investigation of the photic entrainment mechanism at molecular and cellular levels in cutlass fish and can be used in comparative studies of other fishes.

• Steel and Composite Structures
• /
• 제22권5호
• /
• pp.1193-1214
• /
• 2016

In this paper, the 3D stress state and inter-laminar stresses in a rotating thin laminated cylinder shell are studied. The thickness of the cylinder is supposed to be thin and it is made of laminated composite material and can have general layer stacking. The governing equations of the cylindrical shell are obtained by employing the Layerwise theory (LWT). The effect of rotation is considered as rotational body force which is induced due to the rotation of the cylinder about its axis. The Layerwise theory (LWT), is used to discrete the partial differential equations of the problem to ordinary ones, in terms of the displacements of the mathematical layers. By applying the Free boundary conditions the solution of the governing equations is completed and the stress state, the inter-laminar stresses, and the edge effect in the rotating cylindrical shells are investigated in the numerical results. To verify the results, LWT solution is compared with the results of the FEM solution and good agreements are achieved. The inter-laminar normal and shear stresses in rotating cylinder are studied and effects of layer stacking and angular velocity is investigated in the numerical results.