The relationship between the internal labour market and transitions from temporary to permanent employment in Korea

Over the past decade, Korean businesses have experienced significant growth in the proportion of temporary employment. In response, the Korean government has enacted the “Temporary Employment Protection Act” to curb the use of temporary employment. With these legislative changes, Korean employers confront choices about whether to encourage transitions from temporary to permanent employment or to utilise outsourcing/contracting services. The purpose of this study is to explore internal labour markets (ILMs) and investigate why companies are willing to transform temporary employment into permanent employment. Furthermore, in the face of market volatility, we consider how companies are willing to increase the number of temporary workers in order to more easily adjust the numbers and types of human resources, rather than constructing and establishing ILMs within a firm. By investigating the interrelated relationships between ILMs, environmental dynamism, and transitions from temporary to permanent employment status, this study elaborates the features of ILMs in making employment decisions. The statistical results of this study show that structural elements of ILMs facilitate transitions from temporary to permanent employment. Among ILMs, only seniority-based pay plans reduce the number of permanent employees transferred from temporary status when companies experience dynamic changes in their environments. Furthermore, ILMs exerted greater influences over employers’ decisions about transitions from temporary to permanent employment a few years after the enactment of changes in temporary labour laws and regulations. This study shows that the features of an employment system determine companies’ decisions about temporary versus permanent employment. ILMs shape and establish organisational norms and cultural traditions that determine employment structures. Furthermore, institutionalised environments also determine whether employers decide to make transitions from temporary to permanent employment. Future studies should pay attention to the features of employment systems as determinants regarding firms’ human capital.Durant la dernière décennie, les entreprises coréennes ont connu une hausse significative de leur proportion d’emplois temporaires dans leur emploi total. Le gouvernement coréen a adopté la Loi sur la protection de l’emploi temporaire afin de ralentir le recours à cette forme d’emploi. Les employeurs coréens font face au dilemme suivant : favoriser les transitions d’emplois temporaires vers des emplois permanents ou externaliser ou encore sous-contracter certains services. Le but de cette étude est d’explorer les marchés internes du travail et de chercher à savoir pourquoi des entreprises sont disposées à transformer des emplois temporaires en emplois permanents. Par contre, face à la volatilité des marchés, les entreprises auront tendance à accroître le nombre de leurs travailleurs temporaires pour être en mesure d’ajuster plus facilement le nombre et le type de ressources humaines, plutôt que de construire et établir des marchés internes du travail (MIT) en leur sein. En se penchant sur les interrelations entre les MIT, le dynamisme de l’environnement et les transitions d’emplois de statut temporaire à permanent, notre étude cherche à cerner les caractéristiques des MIT eu égard aux prises de décisions en matière d’emploi. Les résultats statistiques de l’étude montrent que certains éléments structurels des MIT facilitent les transitions d’emplois temporaires vers des emplois permanents. Parmi les MIT, seuls ceux comportant des régimes de rémunération basés sur l’ancienneté ont affiché une réduction du nombre d’employés permanents à la suite de conversions d’emplois temporaires en emplois permanents après que les entreprises eurent connus des changements dynamiques dans leur environnement. L’effet des MIT sur les décisions des employeurs de favoriser les transitions d’emplois temporaires vers des emplois permanents se fait davantage sentir après quelques années suivant l’adoption de changements dans les lois et règlements sur le travail temporaire.Cette étude montre que les caractéristiques d’un système d’emploi influent sur les décisions des entreprises dans le choix entre emplois temporaires et emplois permanents. Les MIT configurent et établissent des normes organisationnelles et des traditions culturelles qui à leur tour déterminent les structures d’emplois. De plus, les contextes institutionnels influent aussi sur les décisions des entreprises de favoriser l’une ou l’autre forme d’emploi. Les études à venir sur le sujet devraient mettre davantage l’accent sur les systèmes d’emplois dans la détermination du capital humain des entreprises.En la última década, la proporción de empleo temporal ha experimentado un crecimiento significativo en el medio empresarial coreano. En reacción a esto, el gobierno coreano ha emitido la Ley de protección del empleo temporario para restringir el uso del empleo temporario. Con estos cambios legislativos, los empleadores coreanos se ven confrontados al dilema siguiente: favorecer la transición de empleos temporarios a empleos permanentes o recurrir a la externalización de ciertos servicios y a la sub-contrata. El objetivo de este estudio es de explorar los mercados laborales internos e investigar porqué las empresas estarían dispuestas a convertir empleos temporales en empleos permanentes. Sin embargo, frente a la volatilidad de los mercados, las empresas tendrían tendencia a aumentar el nombre de trabajadores temporales para estar en medida de ajustar más fácilmente la cantidad y el tipo de recursos humanos en lugar de construir y establecer mercados laborales internos en su seno. Abocándose a las interrelaciones entre los mercados laborales internos (MLIs), el dinamismo de los entornos y las transiciones de empleos de estatuto temporario a permanente, nuestro estudio contribuye a precisar las características de los MLI que juegan en las decisiones en materia de empleo.Los resultados estadísticos del estudio muestran que ciertos elementos estructurales de los MLI facilitan las transiciones de empleos temporales en empleos permanentes. Entre los MLI, solo aquellos con regímenes de remuneraciones basados en la antigüedad han experimentado una reducción de la cantidad de empleados y de empleados permanentes como consecuencia de las conversiones de empleos temporales en empleos permanentes después que las empresas habían conocido cambios dinámicos en sus entornos. Es más, los MLI ejercieron una influencia más importante en las decisiones de los empleadores de favorecer las transiciones de empleos temporales en empleos permanentes algunos años después de la adopción de los cambios legislativos y reglamentos sobre el trabajo temporal.Este estudio muestra que las características de un sistema de empleo influencian las decisiones de las empresas sobre la opción entre empleos temporarios y empleos permanentes. Los mercados laborales internos configuran y establecen normas organizacionales y tradiciones culturales, las cuales, a su turno, determinan las estructuras de empleos. Es más, los contextos institucionales influencian también las decisiones de las empresas en cuanto a favorecer una u otra forma de empleo. Los estudios futuros sobre el sujeto deberían poner el acento sobre todo en el rol de los sistemas de empleos en la determinación del capital humano de las empresas

Vision-Based Obstacle Avoidance Strategies for MAVs Using Optical Flows in 3-D Textured Environments

Due to payload restrictions for micro aerial vehicles (MAVs), vision-based approaches have been widely studied with their light weight characteristics and cost effectiveness. In particular, optical flow-based obstacle avoidance has proven to be one of the most efficient methods in terms of obstacle avoidance capabilities and computational load; however, existing approaches do not consider 3-D complex environments. In addition, most approaches are unable to deal with situations where there are wall-like frontal obstacles. Although some algorithms consider wall-like frontal obstacles, they cause a jitter or unnecessary motion. To address these limitations, this paper proposes a vision-based obstacle avoidance algorithm for MAVs using the optical flow in 3-D textured environments. The image obtained from a monocular camera is first split into two horizontal and vertical half planes. The desired heading direction and climb rate are then determined by comparing the sum of optical flows between half planes horizontally and vertically, respectively, for obstacle avoidance in 3-D environments. Besides, the proposed approach is capable of avoiding wall-like frontal obstacles by considering the divergence of the optical flow at the focus of expansion and navigating to the goal position using a sigmoid weighting function. The performance of the proposed algorithm was validated through numerical simulations and indoor flight experiments in various situations

Coordinated Standoff Tracking of Moving Target Groups Using Multiple UAVs

This paper presents a methodology for coordinated standoff tracking of moving target groups using multiple unmanned aerial vehicles (UAVs). The vector field guidance approach for a single UAV is first applied to track a group of targets by defining a variable standoff orbit to be followed, which can keep all targets within the field-of-view of the UAV. A new feedforward term is included in the guidance command considering variable standoff distance, and the convergence of the vector field to the standoff orbit is analyzed and enhanced by adjusting radial velocity using two active measures associated with vector field generation. Moreover, for multiple group tracking by multiple UAVs, a two-phase approach is proposed as a suboptimal solution for a Non-deterministic Polynomial-time hard (NP-hard) problem, consisting of target clustering/assignment and cooperative standoff group tracking with online local replanning. Lastly, localization sensitivity to the group of targets is investigated for different angular separations between UAVs and sensing configurations. Numerical simulations are performed using randomly moving ground vehicles with multiple UAVs to verify the feasibility and benefit of the proposed approach.clos

Disturbance Observer-Based Continuous Finite-Time Sliding Mode Control against Matched and Mismatched Disturbances

In this paper, we propose the disturbance observer-based continuous finite-time sliding mode controller (DOBCSMC) for input-affine nonlinear systems in which additive matched and mismatched disturbances exist. The objective is to show the robustness and disturbance attenuation performance of the closed-loop system with the proposed DOBCSMC subjected to general classes of matched and mismatched disturbances. The proposed DOBCSMC consists of three main features: (i) the nonlinear finite-time disturbance observer to obtain a fast and accurate estimation of matched and mismatched disturbances, (ii) the nonlinear sliding surface to ensure high precision in the steady-state phase of the controlled output, and (iii) the continuous supertwisting algorithm to guarantee finite-time convergence of the controlled output and reduce the chattering under the effect of matched and mismatched disturbances. It should be noted that the existing approaches cannot handle time-varying mismatched disturbances and/or cannot guarantee faster finite-time stability of the controlled output. We prove that the closed-loop system with the DOBCSMC guarantees both finite-time reachability to the sliding surface and finite-time stability of the controlled output to the origin. Various simulations are performed to demonstrate the effectiveness of the proposed DOBCSMC. In particular, the simulation results show that the DOBCSMC guarantees faster convergence of the closed-loop system to the origin, higher precision of the controlled output, and better robustness performance against various classes of (time-varying) matched and mismatched disturbances, compared with the existing approaches

Fuzzy-Based Super-Twisting Sliding Mode Stabilization Control for Under-Actuated Rotary Inverted Pendulum Systems

This paper considers the stabilization problem for under-actuated rotary inverted pendulum systems (RotIPS) via a fuzzy-based continuous sliding mode control approach. Various sliding mode control (SMC) methods have been proposed for stabilizing the under-actuated RotIPS. However, there are two main drawbacks of these SMC approaches. First, the existing SMCs have a discontinuous structure; therefore, their control systems suffer from the chattering problem. Second, a complete proof of closed-loop system stability has not been provided. To address these two limitations, we propose a fuzzy-based (continuous) super-twisting stabilization algorithm (FBSTSA) for the under-actuated RotIPS. We first introduce a new sliding surface, which is designed to resolve the under-actuation problem, by combining the fully-actuated (rotary arm) and the under-actuated (pendulum) variables to define one sliding surface. Then, together with the proposed sliding surface, we develop the FBSTSA, where the corresponding control gains are adjusted based on a fuzzy logic scheme. Note that the proposed FBSTSA is continuous owing to the modified super-twisting approach, which can reduce the chattering and enhance the control performance. With the proposed FBSTSA, we show that the sliding variable can reach zero in finite time and then the closed-loop system state converges to zero asymptotically. Various simulation and experimental results are provided to demonstrate the effectiveness of the proposed FBSTSA. In particular, (i) compared with the existing SMC approaches, chattering is alleviated and better stabilization is achieved; and (ii) the robustness of the closed-loop system (with the proposed FBSTSA) is guaranteed under system uncertainties and external disturbances

A review of source term estimation methods for atmospheric dispersion events using static or mobile sensors

Understanding atmospheric transport and dispersal events has an important role in a range of scenarios. Of particular importance is aiding in emergency response after an intentional or accidental chemical, biological or radiological (CBR) release. In the event of a CBR release, it is desirable to know the current and future spatial extent of the contaminant as well as its location in order to aid decision makers in emergency response. Many dispersion phenomena may be opaque or clear, thus monitoring them using visual methods will be difficult or impossible. In these scenarios, relevant concentration sensors are required to detect the substance where they can form a static network on the ground or be placed upon mobile platforms. This paper presents a review of techniques used to gain information about atmospheric dispersion events using static or mobile sensors. The review is concluded with a discussion on the current limitations of the state of the art and recommendations for future research.close

Persistent standoff tracking guidance using constrained particle filter for multiple UAVs

This paper presents a new standoff tracking framework of a moving ground target using UAVs with limited sensing capabilities and motion constraints. To maintain persistent track of the target even in case of target loss for a certain period, this study predicts the target existence area using the particle filter and produces control commands that ensure that all predicted particles can stay within the field-of-view of the UAV sensor at all times. To improve target position prediction and estimation accuracy, the road information is incorporated into the constrained particle filter where the road boundaries are modelled as inequality constraints. Both Lyapunov vector field guidance and nonlinear model predictive control-based methods are applied, and the characteristics of them are compared using numerical simulations