• The Korean Journal of Applied Statistics
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• v.37 no.3
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• pp.265-282
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• 2024

Research in the area of financial portfolio optimization, with the dual goals of increasing expected returns and reducing financial risk, has actively explored various risk measurement indicators. At the same time, the incorporation of various penalty terms to construct efficient portfolios with limited assets has been investigated. In this study, we present a novel portfolio optimization formula that combines the mean-shortfall portfolio and the SLOPE penalty term. Specifically, we formulate this optimization expression, which differs from linear programming, by introducing new variables and using the alternating direction method of multipliers (ADMM) algorithms. Through simulations, we validate the automatic grouping property of the SLOPE penalty term within the proposed mean-shortfall portfolio. Furthermore, using the model introduced in this paper, we propose and evaluate four different types of portfolio compositions relevant to real-world investment scenarios through empirical data analysis.

• Journal of Biomedical Engineering Research
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• v.36 no.5
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• pp.211-220
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• 2015

Recently, model-based iterative reconstruction (MBIR) has played an important role in transmission tomography by significantly improving the quality of reconstructed images for low-dose scans. MBIR is based on the penalized-likelihood (PL) approach, where the penalty term (also known as the regularizer) stabilizes the unstable likelihood term, thereby suppressing the noise. In this work we further improve MBIR by using a more expressive regularizer which can restore the underlying image more accurately. Here we used a spline regularizer derived from a linear combination of the two-dimensional splines with first- and second-order spatial derivatives and applied it to a non-quadratic convex penalty function. To derive a PL algorithm with the spline regularizer, we used a separable paraboloidal surrogates algorithm for convex optimization. The experimental results demonstrate that our regularization method improves reconstruction accuracy in terms of both regional percentage error and contrast recovery coefficient by restoring smooth edges as well as sharp edges more accurately.

• International Journal of Advanced Culture Technology
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• v.7 no.3
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• pp.97-102
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• 2019

This study suggests a solution of an incentive system from the viewpoint of the external effect on the renting of firefighting qualifications and on rental agencies. Currently, the Human Resources Development Service of Korea does not have a penalty for neglecting to perform a search into qualification lending and rental agencies. In the short term, the penal clause should be strengthened so that companies and qualification holders cannot borrow or lend their qualifications. In addition, the Human Resources Development Service of Korea will increase the number of personnel dedicated to investigating the loaning of qualifications. It is necessary for the government to establish a penalty for neglecting to investigate the lending of qualifications for the Human Resources Development Service of Korea. In the long term, the state needs to make only minimal regulations. Also, the state needs to make companies and qualification holders feel like they benefit more when they are not borrowing or lending qualifications. The anticipated effect of this study is that the government will intervene appropriately by applying firefighting qualifications according to market principles. It can also be used as a basis for the revision of related laws on the renting of national technical qualification certificates and the investigation of rental agencies.

• Safety and Health at Work
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• v.12 no.1
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• pp.20-27
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• 2021

Background: Incentive and penalty (I/P) programs are commonly used to increase employees' safety outcomes, but its influence on employees' safety outcomes is under-investigated. Moreover, under developed economies lack safety culture and there is dearth of literature focusing on empirical studies over there [1]. Based on these gaps, this study attempts to see the impact of I/P programs on safety outcomes in a developing country. Methods: The study was carried out in three stages, where Stage I revealed that selected 45 organizations were deficit of safety culture and practices, while only three firms were found good at safety practices. At Stage II, these three firms were divided in two clusters (groups), and were probed further at Stage III. At this stage group, one was manipulated by providing incentives (experimental group) and employees' responses in terms of safety motivation and performance were noticed. Results: It was observed that the experimental group's safety motivation and performance had improved (both for immediate and 1-month later performance). The results were further probed at Phase 3 (after 3 months), where it was found that the benefits of I/P programs were not long lasting and started replenishing. Conclusion: Findings of the study helped researchers conclude that safety incentives have only short-term influence on safety outcomes, while a long-term and permanent solution should be found.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.70
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• pp.39-65
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• 2016

On 2013 the English court delivered a decision that the payment obligation under time charter party is a condition. According to this judgement, The Astra, a breach of the obligation to pay hire on time entitles the owner both to withdraw the ship and sue the charterers for damages for the difference between the contract and market rate for the remainder of the contracted period. On 2015, however, the English court stood at the other side. In Spar Shipping, the court confirmed that the obligation to pay hire is not a condition of the contract but an "innominate term" - from the charterers' breach ship owners can exercise their contractual right to withdraw, but owners' right to sue for damages depends on whether the charterers have deprived the owners of the substantial benefit of the contract, or shown an intention to do so. This article aims to compare both decisions over the points that (1) the importance of on-time payment under a time charter party, (2) as a critical and main question in this article, whether the mattered payment clause is a condition or innominate term, (3) whether the on-time payment clause is merely a penalty or a reasonable liquidated damage. Based on various reasons, I am on a position that the payment of hire is not a condition but an innominate term. Default in punctual payment by a charterer, in the absent of clear contractual agreement, needs to be decided further whether that breach removes the substantial benefit of the contract from the owners.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2242-2244
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• 2004

This paper deals with the design of a reduced-order stabilizing controller for the linear system. The coupled lineal matrix inequality (LMI) problem subject to a rank condition is solved by a sequential semidefinite programming (SDP) approach. The nonconvex rank constraint is incorporated into a strictly linear penalty function, and the computation of the gradient and Hessian function for the Newton method is not required. The penalty factor and related term are updated iteratively. Therefore the overall procedure leads to a successive LMI relaxation method. Extensive numerical experiments illustrate the proposed algorithm.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.13 no.3
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• pp.169-180
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• 2009

A discontinuous Galerkin method with interior penalty terms is presented for linear Sobolev equation. On appropriate finite element spaces, we apply a symmetric interior penalty Galerkin method to formulate semidiscrete approximate solutions. To deal with a damping term $\nabla{\cdot}({\nabla}u_t)$ included in Sobolev equations, which is the distinct character compared to parabolic differential equations, we choose special test functions. A priori error estimate for the semidiscrete time scheme is analyzed and an optimal $L^\infty(L^2)$ error estimation is derived.

• Communications for Statistical Applications and Methods
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• v.18 no.3
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• pp.357-365
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• 2011

This paper investigates a penalized likelihood method for estimating the parameter of normal mixtures in multivariate settings with full covariance matrices. The proposed model estimates the number of components through the addition of a penalty term to the usual likelihood function and the construction of a penalized likelihood function. We prove the consistency of the estimator and present the simulation results on the multi-dimensional nor-mal mixtures up to the 8-dimension.

• Journal of applied mathematics & informatics
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• v.4 no.1
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• pp.167-178
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• 1997

In this paper we present an application to airfoil design of an optimum design method based on optimal control theory. The method used here transforms the design problem by way of a change of variable into an optimal control problem for a distributed system with Neumann boundary control. This results in a set of variational inequalities which is solved by adding a penalty term to the differential equation. This si inturn solved by a finite element method.

• The Korean Society of Law and Medicine
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• v.8 no.1
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• pp.215-234
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• 2007

The mission of the doctors is to take care of human life, body and health through the medical behaviors such as diagnosis and treatment. Under this job propensity, the doctors have care duty to take the best actions required to prevent the risk according to the patients' specific disease status. Such care duty of the doctor may be evaluated based on the medical behavior level at the medical institution and clinical medical study field. Such medical level should be understood in the normative level, considering the treatment environment, condition and specialty of the behavior, because it means the medical common sense known and acknowledged to the normal doctors. While the criminal suit requires the evidence for no doubt conviction, the civil suit requires more eased different standard. The results between the criminal and civil sentence may be different, because the confirmed former case may lead to long-term imprisonment and even death penalty, while the latter case puts only monetary penalty on the defeated party.